Case No. 1998 FOLIO No.1708
BAILII Citation Number: [2000] EWHC 227 (Comm)
IN THE HIGH COURT OF JUSTICE
QUEEN’S BENCH DIVISION
COMMERCIAL COURT
Date: 31st July 2000
THE HONOURABLE MR JUSTICE MOORE-BICK
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BETWEEN

	JAN DE NUL (UK) LIMITED	Claimant	
	and		
	N.V. ROYALE BELGE	Defendant	

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Mr. Alistair Schaff Q.C. and Mr. Simon Kerr instructed by Collins Stone & Thompson appeared for the claimant

Mr. Nicholas Hamblen Q.C. and Mr. Michael Ashcroft instructed by Clyde & Co appeared for the respondent.
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JUDGMENT

The Hon. Mr. Justice Moore-Bick: 

Introduction 

1. This action arises out of capital dredging operations carried out in Southampton Water between 1996 and 1997 in the course of which the depth of the main shipping channel to the Prince Charles Container Port was increased and the course of the channel straightened. The port of Southampton is operated by Associated British Ports ("ABP"), a statutory corporation formerly known as the British Transport Docks Board established under section 1 of the Transport Act 1962. Its constitution, powers and duties are now regulated by the Transport Act 1981. The contractor employed by ABP to carry out the work was the claimant, Jan de Nul (UK) Ltd ("Jan de Nul"), the English subsidiary of Jan de Nul N.V., a Belgian company specialising in dredging operations around the world. The defendant in this action, N.V. Royale Belge, is a Belgian insurance company with which Jan de Nul insured its liabilities to third parties arising out of the works. 

2. The port of Southampton lies on the confluence of the rivers Test and Itchen, Southampton Water being the name given to that part of the estuary which extends from the lower tidal reaches of the Test and the Itchen to the Solent. Prior to October 1996 a navigation channel was maintained at an advertised depth of 10.2m from the Solent to the container port which lies at the head of Southampton Water in the lower reaches of the Test. A similar, though slightly shallower, channel was maintained leading from the main channel to a number of commercial berths in the lower reaches of the Itchen as well as the Empress Dock. Just downstream of the container port there is a large area known as the Upper Swinging Ground which is maintained to the same depth as the channel to enable vessels using that part of the port to turn. The Middle and Lower Swinging Grounds provide similar facilities further down the channel. The whole of the North-eastern side of the estuary above the point where the Itchen enters Southampton Water is occupied by Southampton Docks which lie directly on the main navigation channel. On the South-western side, however, the depth of water outside the main channel is very limited and this side of the estuary is mainly occupied by a variety of small commercial organisations and yacht clubs. The only exception of any significance is the Marchwood military port which lies opposite the lower end of the Western Docks. An advertised depth of 8m is maintained throughout about two thirds of the area of the military port extending out to the main channel; in the remainder of the port an advertised depth of 4.9m is maintained. 

3. In order to enable larger vessels to use the container port ABP decided in 1996 to increase the depth of the main navigation channel and the Swinging Grounds from 10.2m to 12.6m and to straighten the channel slightly at a point known as Gymp Elbow between the Lower and Middle Swinging Grounds. This involved capital dredging, that is, the removal of previously undisturbed material from the bed of the channel. The material forming the bed of the estuary varied throughout its length, but two sections are of particular importance in relation to the present case because in each of them the sub-soil was predominantly composed of a material which was generally referred to as "greensand" but which was in fact clay containing a high proportion of glauconite. Glauconite is grey-green in colour and it is that which has given rise to the description "greensand". Glauconite is encountered in very fine particles which have a tendency to form "card-house" structures, that is, they agglomerate edge to edge to form loose structures which have a large volume relative to their density and which therefore remain in suspension much longer than other materials of a broadly similar type. Downstream from a point approximately 7,000m from the mouth of the channel the sub-soil was composed of greensand of a more or less homogeneous nature. From that point upstream as far as and including the Upper Swinging Ground the sub-soil was composed of laminated greensand, that is, clay containing glauconite interspersed with discrete bands of fine-grained sand. 

4. The sub-soil of the channel was too hard to enable dredging to be carried out by simple trailing suction methods. Jan de Nul therefore used a cutter suction dredger to pre-cut the material. A cutter suction dredger ("CSD"), as its name implies, is equipped with a mechanical cutting head which loosens the soil enabling it to be pumped into barges alongside for removal and disposal. Removal of soil in this manner is a slow operation, however, and in the present case it was considered preferable to discharge the cut material back onto the bed of the channel to await later removal by a trailing suction hopper dredger ("TSHD") which would carry out the removal and disposal of the spoil more efficiently. This latter type of dredger is equipped with a suction head capable of picking up loose material which is pumped into hoppers on board. It is capable of removing material much more quickly than it can be cut by a CSD. This method of working which involved pre-cutting the soil and returning it to the channel inevitably caused a certain amount of material to be put into suspension as did the trailing operation since the dredgers which removed the pre-cut material were permitted to use what is known as the "overspill" method. Material is pumped from the sea bed as a fluid mixture with water and is discharged into the dredger’s hoppers where the heavy material rapidly sinks to the bottom. Once the hoppers are full water is discharged continuously until the hoppers are filled to a pre-determined extent with solid material. However, water discharged during the overspill phase will inevitably carry with it a certain amount of fine material in suspension and care must be taken to ensure that the maximum hopper loading and the duration of the overspill phase take proper account of the nature of the material being dredged. The tender documents in the present case indicated that hoppers could be loaded to 80% capacity, but as will be seen that proved to be wrong. In the present case Jan de Nul calculated on the basis of trials which they carried out before beginning the work that all the material put into suspension would settle within the area of the channel from which it would be removed as part of the contract work. 

5. Contrary to Jan de Nul’s expectations, however, the material put into suspension did not settle within the area of the channel. Substantial amounts were carried away from the channel by the action of the tide and settled in other parts of the estuary. The commercial berths in the lower reaches of the Itchen were affected, but much of the silt was deposited at the head of the estuary and in the general area of the Marchwood basin which lies on the South-western side of the estuary opposite the Western Docks. Complaints were made by the operators of wharves, by yacht clubs whose moorings were affected and by others to whom I shall refer in more detail at a later stage. These complaints were initially directed to ABP which took some measures using its own dredgers to remove silt from various areas. In doing so it incurred substantial costs. ABP also called upon Jan de Nul to remove silt by way of remedial works which it insisted Jan de Nul was obliged to carry out as part of its obligations under the dredging contract. Jan de Nul never formally accepted that it was obliged to carry out remedial work, but it did eventually take measures to remove the silt from the remaining areas using its own equipment. The total cost incurred by ABP and Jan de Nul between them came to a little over £2½ million, of which some £778,000 represented expenses incurred by ABP which it withheld from amounts due to Jan de Nul under the dredging contract. In these proceedings Jan de Nul seeks to recover under its policy with Royale Belge the whole of the cost of removing the silt from various parts of the estuary. It does so on the basis that by causing silt to be deposited in areas of the estuary which affected their operations or interests it incurred liabilities to a number of third parties and to ABP which fall within the scope of the cover and that the expenses which it incurred fairly reflect the measure of those liabilities. ABP was itself a co-insured under the policy and on 28th May 1999 assigned any claim it might have under the policy to Jan de Nul. Jan de Nul therefore also seeks, if necessary, to recover from Royale Belge whatever sums ABP was itself entitled to recover under the policy. 

 The policy of insurance 

6. The policy of insurance was effected through a firm of brokers in Antwerp, J. Van Breda & Co. It contains no choice of law which is applicable to the present case, but in view of the nature of the contract there was no dispute that the only realistic choice must be between English and Belgian law. However, since neither party suggested that Belgian law differs from English law in any material respect, I approach the issues in this case on the assumption that the contract is governed by English law. 

7. The contract is contained in three documents: the General Conditions, the Brokers’ Clauses and the Special Conditions. All the documents have been provided by the insurers in English, although in the case of the General Conditions the French text is stated to be the governing text and in the case of the Brokers’ Clauses the Dutch text is said to govern. However, neither party sought to place any reliance on the French or Dutch texts and I have therefore confined myself to the English text. The General Conditions are a standard form document. They form the basis of the contract in the sense that they contain the primary insuring clause, definitions, exclusions, and other fundamental terms of cover, but they also contain whole sections which have no application to the present contract. The Brokers’ Clauses appear to be a set of standard clauses devised by J. Van Breda & Co. and approved by Royale Belge for use in policies effected through them. They state that they take precedence over the General Conditions, except where those are more favourable to the insured. The Brokers’ Clauses also provide that the Special Conditions shall take precedence over all others. The Special Conditions have clearly been drawn up to embody terms which relate to this specific contract. They include, for example, the identity of the insured, a description of the insured activities and the dates of cover, as well as clauses relating to the nature and extent of the cover provided. 

8. At a later stage in this judgment it will be necessary to set out at length some of the provisions of the policy, but for the moment it is sufficient to mention only those clauses which define the scope of the primary cover. They are as follows: 

    GENERAL CONDITIONS 

Section 1 - AIM OF THE COVER 

1.1 Legal Grounds - Covered activities - Insured Persons 

1.1.1 The insurers cover the insured’s extracontractual liability for damage caused to third parties during the operation of the business in connection with the activities described in the special conditions. 

    . . . . . . . . . . . . . . . . . . . . 

By extension the contractual liability is covered if it results from a fact which on itself, can give rise to extracontractual liability; yet, the cover is limited to the compensation that would be owed if the liability claim had been given an extracontractual ground. 

    . . . . . . . . . . . . . . . . . . . . 

1.2 Damage covered 

1.2.1 Bodily injury and property damage are covered 

1.2.2 The covers stipulated in the special conditions for bodily injury and property damage are extended, within the above-mentioned limits, to immaterial damage. Cover is afforded for consequential immaterial damage and for non-consequential immaterial damage provided the latter is caused by an abnormal occurrence which is unintentional and unexpected for the policyholder, his entities or officers. 

Immaterial damage consequential to non-covered bodily injury or property damage is excluded. 

    BROKERS’ CLAUSES 

    . . . . . . . . . . . . . . . . . . . . 

 9. Liability of the Insured 

This insurance covers the civil extra-contractual liability of the insured for physical and material damage, in so far as the liability is in connection with his professional or business activities and the loss caused is to a third party or parties. It also covers immaterial loss such as stoppages of work and loss of profit or use resulting from a covered physical or material damage; immaterial damage resulting from a non-covered damage is not insured, except as provided in Article 11.1 (neighbour nuisance); immaterial damage which does not result from bodily injury or property damage is only covered if it is caused by abnormal or unforeseen occurrence beyond the control of the management, that is, the company director and the members of the general or technical management responsible for the definition and implementation of working methods, if they act within this context not as executing employees. Contractual liability is covered if it results from a cause that can, in itself, give rise to extra-contractual liability; the guarantee is however limited to the amount of compensation due if the claim had an extra-contractual basis.    . . . . . . . . . . . . . . . . . . . . 

 10. Explanation of Risk 

The guarantee of this policy is general and extends to all cases in which claims can be made against the third party liability of the insured. . . . . . . 

    SPECIAL CONDITIONS 

Insured activities: 

DREDGING OPERATIONS IN THE SOUTHAMPTON PORT 

Insureds: 

Within the insured business, the Principal of the works, ASSOCIATED BRITISH PORTS - PORT of SOUTHAMPTON, is insured as well. That party remains, however, a third party with respect to the other parties." 

9. In the light of these provisions it was common ground that the policy under which Jan de Nul and ABP were co-insureds provided cover against liability incurred to third parties, ABP also being treated as a third party for these purposes in relation to Jan de Nul. Accordingly, Mr. Schaff Q.C. on behalf of Jan de Nul accepted that in order to make a claim under the policy in respect of the costs incurred in removing silt deposited in areas outside the channel it was necessary for Jan de Nul to establish either that it had incurred a liability to third parties adversely affected by it, or, insofar as it sought to rely on the sue and labour provisions in the policy, that it took reasonable steps to avoid incurring such a liability. 

 The third party claimants 

10. It is convenient at this point to identify more precisely the various third parties who complained of the deposit of silt and to whom Jan de Nul says it incurred liability. Leaving aside unidentified members of the public who complained about a reduction in the depth of water available in the Marchwood Basin but who were unable to show that they had suffered any particular damage, the following groups of claimants are identified in schedule 2 to the points of claim: 

 (i) the Ministry of Defence on behalf of the Crown in respect of interference with the use of Marchwood military port; 

 (ii) Southern Water Services Ltd in respect of interference with the use of the berths at Slowhill Copse and Weston Jetty; 

 (iii) Marchwood Wharfage Ltd in respect of interference with the Marchwood Wharf; 

 (iv) Husband’s Ltd, yacht builders and repairers, in respect of interference with its moorings, jetty and slipway; 

 (v) Marchwood Yacht Club and various individuals in respect of the interference with the use of moorings in the Marchwood Basin and ABP as owner of the river bed in that area; 

 (vi) ABP in respect of interference with berths 30-36 and the Itchen approaches; 
 (vii) ABP, Marchwood Wharfage, Husband’s Shipyard and others in relation to the obstruction of the Marchwood Channel and Basin; 

 (viii) the Waterside Fisherman’s Association in respect of damage to clam and oyster beds in Dibden Bay; 

 (ix) Hampshire Wildlife Trust in respect of deposits of silt on parts of the nature reserve at Eling and Redbridge Marshes. 

 The nature of the rights which these various claimants enjoyed in the river bed and the adjacent land varied, as did the nature of their complaints, and it will be necessary, therefore, to consider their positions individually at a later stage. 

 The planning and execution of the works 

11. Whether Jan de Nul incurred any legal liability to any of these claimants turns on the application of the law relating to the torts of negligence, nuisance and public nuisance. In those circumstances Jan de Nul did not shrink from contending that from the outset it had itself, together with ABP, been negligent towards the occupiers of property lying along the estuary in planning and carrying out the work, and that if proper care had been taken, the deposit of silt in substantial quantities outside the channel could and would have been avoided altogether. It is convenient therefore to begin by considering the manner in which the work was carried out and in particular whether there was negligence on the part of Jan de Nul or ABP. 

12. The instructions to tenderers included a requirement that the contractor should examine the site and its surroundings and satisfy itself as to its nature. In keeping with that approach the conditions of contract on which the tender was based provided that the contractor should be deemed to have inspected and examined the site and to have satisfied itself as to the nature of the ground and the sub-soil. As between ABP and Jan de Nul, therefore, the responsibility for carrying out any further investigation into the nature of the sub-soil which might be called for rested with Jan de Nul. A negligent failure to carry out these duties may well have given rise to a liability to ABP, but in relation to third parties the question is not whether Jan de Nul negligently failed to carry out its duty under the contract but whether Jan de Nul or ABP was in breach of a common law duty of care towards any of those who subsequently complained of the deposit of silt in areas in which they were interested. The existence of a duty of care at common law depends on foreseeability that a failure to take reasonable care may cause harm of a particular kind to another person, a sufficient degree of proximity between the wrongdoer and that other person, and a recognition that it would in the circumstances be fair, just and reasonable in all the circumstances to impose a duty of care on the wrongdoer. In the present case none of these factors was the subject of serious debate because Royale Belge did not challenge the assertion, implicit in Jan de Nul’s case, that ABP as the employer and Jan de Nul as the contractor carrying out major dredging works in an area of this kind each owed a duty to the owners and occupiers of property along the margins of the estuary to take reasonable care to prevent damage by the deposition of silt. The debate between the parties therefore concentrated entirely on two questions: did Jan de Nul or ABP fail to exercise all reasonable skill and care in and about the works; and was the damage suffered by the third parties damage of a kind for which they are in law liable? 

13. The expert witnesses, Dr. Volker Patzold and Mr. Wilfried De Keyser, agreed that however carefully major dredging operations of the kind involved in this case are conducted they are bound to cause a certain amount of fine material to be put into suspension and that there is therefore a risk that some material will be deposited outside the area of the dredging works. Broadly speaking, the extent to which material will pass into suspension will depend on the nature of the material being dredged and the manner of working. Whether material which passes into suspension is likely to be deposited outside the working area depends to a large extent on the time it takes to settle and the action of natural forces, in particular currents and tides. The documents on the basis of which Jan de Nul and other contractors were invited to tender for the works included reports prepared for ABP by consultants in February 1994 which contained detailed information about the physical nature and properties of the sub-soil in the areas to be dredged. It is unnecessary to deal with the contents of these reports in any detail, save in two respects. The first concerns the method of sampling of the sub-soil. Samples were taken at intervals along the channel by vibrocore. The equipment was designed to penetrate up to 4m below the surface, but in some locations the sub-soil was too dense to allow penetration of much more than 1m. That was of potential significance given that the depth of the channel was to be increased by almost 2.5m. The second concerns the information about the physical nature of the sub-soil. Grain size analyses of material obtained from the vibrocore samples were carried out using standard methods in order to provide information about the relative proportions of particles of different sizes of which the sub-soil was composed. However, the method of analysis which was used for this purpose did not enable any measurement to be made of the distribution of particles below 63? in size. The consultants who produced the report made an informed assessment of the likely proportions of fine particles of less than 63? in diameter which they incorporated into the particle size distribution graph included in their report, but, as later became apparent, their estimate was inaccurate in that it failed to reflect the unusually high number of very fine particles, in particular particles with a diameter of less than 20?. The reports did refer to the presence of glauconite in the areas which I have mentioned, but did not refer to its propensity to form card-house structures. 

 Negligence on the part of Jan de Nul 

14. Jan de Nul did carry out further investigations into the nature of the sub-soil where the vibrocores obtained for the tender documents had not achieved sufficient penetration, but it did not commission a mineralogical investigation into the nature of the glauconite even though it was unfamiliar with its properties, nor did it obtain a grain size analysis of material with a diameter of less than 63µ. In the event the presence of glauconite in substantial quantities proved to be a very significant factor because the method of working adopted by Jan de Nul, in particular the use of pre-cutting and overspill dredging, resulted in substantial quantities of very fine material passing into suspension and the propensity of that material to form card-house structures resulted in its remaining in suspension, and thus exposed to the action of wind and tide, for much longer than would otherwise have been the case. It was this combination of factors which in due course led to the deposit of substantial quantities of silt in many parts of the estuary outside the limits of the dredged channel. It was later discovered that 90% of the silt deposited outside the channel was composed of particles less than 20µ in diameter. 

15. After it had been awarded the contract Jan de Nul carried out dredging trials in order to evaluate, among other things, the efficacy of its proposed working methods. During the latter part of August and early September 1996 the TSHD Cristoforo Colombo carried out trials in order to confirm Jan de Nul’s original assessment that the sub-soil in the areas of greensand and laminated clay beds was too dense to allow trailer dredging and would require cutting. On various occasions while the Cristoforo Colombo was removing overlying sediment water quality analyses were carried out to ascertain the rate of settlement of the suspended material which was discharged overboard during the overspill phase. These indicated that all the material settled back into the dredged channel within a distance of about 500m. In September and October Jan de Nul carried out trials of the pre-cutting and trailing method in the greensand area, but it concentrated its investigations on the extent of bulking caused by pre-cutting and on the feasibility of removing the pre-cut material by trailing. Unfortunately, no water quality analyses were carried out during these trials and no similar trials were carried out in the area of the laminated beds. 

16. Work began in earnest in the middle of October 1996. The CSD Marco Polo began straightening the channel at the Gymp Elbow, loading the cut material directly into barges because at that point there was insufficient depth of water to allow material to be deposited back into the channel. At the same time the Cristoforo Colombo began removing the overlying silt from the greensand further down the channel. Work at the Gymp Elbow was completed by 24th November and the Marco Polo then began pre-cutting in the main area of the channel. During this phase of the work the pre-cut material was discharged back into the channel where it lay pending removal by the trailers. This stage of the pre-cutting work was substantially completed by 18th January 1997. 

17. Originally Jan de Nul had intended to employ its own TSHD, Mercator, then under construction, to remove the bulk of the pre-cut material, but the vessel’s delivery was delayed and Jan de Nul therefore chartered a vessel of similar capacity, the Amsterdam. In mid-December she began removing pre-cut material working from between a point downstream of the confluence of the Itchen and the Test up to the southern end of the Western Docks. Shortly after the Amsterdam began work the first indications that there might be problems began to appear. On 18th December the port engineer informed Jan de Nul that vessels had reported problems passing through the Upper Swinging Ground. One vessel had touched the bottom and another had experienced difficulty in manoeuvring. In addition, there had been an appreciable build-up of silt at berths 202 and 204, two of the berths near the head of the channel. During the following days it became apparent that the Amsterdam was performing far less efficiently than had been expected because material was not settling out in the hoppers as quickly as had been predicted. At that stage, however, Jan de Nul was unable to identify the cause of the problem. Finally, at about the same time the first complaints of siltation were received from other organisations which used the estuary. At the progress meeting on 9th January 1997 ABP reported that a complaint had been received from Southern Water about siltation at its berth at Slowhill Copse and that Marchwood Sailing Club had complained that its mooring area and slipway were being affected. 

18. In the view of Dr. Patzold, the fact that a large amount of the material which had to be removed was clay and silt did not itself present an unusual problem. Although he and Mr. De Keyser agreed that the particular type of sub-soil which existed in this case is not commonly encountered, he thought that the appearance of the material together with the description contained in the tender documents ought to have alerted Jan de Nul to the possibility of excessive amounts of silt being deposited around the estuary. He considered that Jan de Nul was negligent at the outset in failing to make further enquiries about the nature of glauconite and in failing to obtain a full grain size analysis of particles below 63µ in diameter. Because of the propensity of glauconite to form card-house structures he considered it to be of real importance for a contractor undertaking a job of this kind to be aware of the precise mineralogical composition of the material with which he was dealing. He also drew attention to the fact that the tender documents did not contain any information about the distribution of particles within the range 0-63µ although they represented a significant proportion of the material to be dredged and would have the most significant influence on the rate at which material in suspension settled out. He considered that Jan de Nul ought also to have carried out a study on the behaviour of the pre-cut material and ought to have made its own calculations of the settlement of material in the dredgers’ hoppers rather than relying on the loading rates indicated in the tender documents. He criticised Jan de Nul for having failed to monitor the amount and behaviour of material in suspension during the second dredging trial when the pre-cutting and trailing methods were being evaluated. Mr. De Keyser, on the other hand, was much less critical of Jan de Nul in his report. He considered that the steps it had taken to establish the nature and properties of the sub-soil were normal and in accordance with good industry practice. He accepted that Jan de Nul had not carried out tests to investigate the behaviour of the material, but did not consider that contractors would normally expect to carry out additional investigations of the kind suggested by Dr. Patzold. 

19. Although Dr. Patzold and Mr. De Keyser have both had a great deal of experience in dredging operations all over the world, their experience has diverged to some extent during the last ten years. During this period Dr. Patzold has been continuously involved in the industry and has acted on many occasions as a consultant advising on major projects. Mr. De Keyser has spent the bulk of this period as a consultant to the insurance industry, mainly in the capacity of a loss adjuster, and although he has maintained a close contact with the specialised world of the dredging industry, he has not had the same practical experience as Dr. Patzold. When considering their evidence of standards and practices in that industry, therefore, I prefer the evidence of Dr. Patzold who in my judgment was able to speak with greater authority about the way in which projects of this kind were being approached by contractors at the time in question. However, it is also fair to say that by the time both experts had finished giving evidence there was less between them than might at first have been expected. Mr. De Keyser agreed that the contractor has a duty to avoid as far as possible the deposit of silt outside the area being dredged and that for that purpose, as well as in his own interests, he ought to satisfy himself about the nature and properties of the sub-soil. He accepted that a full grain size analysis of particles of less than 63µ in diameter would have been inexpensive and easy to obtain; he also accepted that a prudent contractor who was unfamiliar with the nature of glauconite ought to have made the necessary enquiries about its characteristics. 

20. Dr. Patzold considered that Jan de Nul should have investigated the likely behaviour of silt in suspension more thoroughly by carrying out trials in different parts of the channel and by monitoring of the behaviour of the material in suspension more closely. Mr. De Keyser agreed with Dr. Patzold that the risk of small particles going into suspension was greater in the area of the laminated sands than in more homogeneous ‘greensands’ and he was unable to support Jan de Nul’s failure to carry out any trials in the area of the laminated sands. The experts agreed that the poor performance of the Amsterdam was due to the fact that so much of the material was in the form of very fine particles which remained in suspension and were discharged with the overspill water. Mr. De Keyser accepted that if full pre-cutting and trailing trials had been carried out in the laminated sands as well as the greensand, Jan de Nul would probably have become aware of the difficulties subsequently encountered by the Amsterdam before work started. In my view this was a significant piece of evidence because Mr. De Keyser accepted in his original report that Jan de Nul had failed to respond adequately to this problem when it did eventually manifest itself in December 1996. He said, and I accept, that it should have alerted Jan de Nul to the very high volume of fine particles remaining in suspension which should in turn have led to an appreciation of the need for a change in methods of working. In those circumstances about half the damage could have been avoided. 

21. One issue of importance, however, on which Dr. Patzold and Mr. De Keyser did disagree was whether a prudent contractor ought to have carried out a behavioural study based on a mathematical model of the estuary in order to investigate the likelihood of silt being deposited outside the limits of the channel. Dr. Patzold said that within the last ten years it has become much more common in the dredging industry to carry out studies of that kind and in his supplemental report he referred to five examples with which he was personally familiar. Mr. De Keyser, on the other hand, said that it was most unusual for a contractor to carry out such a study at his own expense. For the reasons I have already given, I prefer Dr. Patzold’s evidence on this question, although I have borne in mind that the present contract was made in 1996 and that only two of the specific examples put forward by Dr. Patzold relate to contracts made at an earlier date. 

22. In the light of this evidence I am satisfied that Jan de Nul was negligent towards the owners and occupiers of property adjoining the estuary in failing to exercise reasonable care to avoid damage by siltation. Siltation of adjacent areas is a well-recognised risk of any large-scale dredging operations and the likelihood of its occurring depends to a great extent on the nature of the material to be dredged and the working methods employed. It goes without saying that in deciding what methods to employ the contractor must take account of the material he is dealing with. In the present case the information contained in the tender documents was clearly incomplete in some important respects. Jan de Nul did have further vibrocore samples taken, but it did not obtain a further grain size analysis or a full mineralogical study of the glauconite, both of which were needed to enable it to make a proper assessment of the material. Neither of these would have been expensive and Mr. Hamblen Q.C. was right in my judgment to accept that both of them should have been obtained. If these further studies had been carried out they would have alerted Jan de Nul to the likelihood that large amounts of fine particles were likely to be put into suspension and were likely to remain in suspension for much longer than would ordinarily be the case. This in turn ought to have called into question both the general method of working which involved pre-cutting and trailing and the use of the overspill dredging method by the trailers. Moreover, although these studies would not themselves have provided any direct indication of the likelihood that silt would settle in substantial quantities outside the dredged channel, they should have alerted Jan de Nul to that possibility because of the increased exposure of material in suspension to the action of the wind and tide. In order to assess the risk of the deposit of silt in other parts of the estuary it would have been necessary to make use of a mathematical model of the kind mentioned by Dr. Patzold. In view of the risks involved in dredging glauconite by the methods which Jan de Nul proposed to use I think that there is a strong argument for saying that such a model ought, if necessary, to have been constructed in order to assess the effect of wind and tide on material in suspension, but it is unnecessary to form any final view on that matter given the fact that a model was already available in the possession of ABP. There had been a high level of co-operation between ABP and Jan de Nul both during and after the tender stage and Jan de Nul ought in my view to have raised the matter with ABP. Had a request been made, I have no doubt that ABP, which was equally interested in avoiding siltation of other parts of the estuary, would have allowed the model to be used for this purpose. I am satisfied, therefore, that Jan de Nul was negligent at the planning stage both in failing to carry out these further studies and in failing to carry out trials of the pre-cutting and trailing method in the area of the laminated sands. 

23. Both Dr. Patzold and Mr. De Keyser were of the opinion that the events which occurred during the latter part of December 1996 and the early part of January 1997 ought to have alerted a prudent contractor to the fact that the existing method of working was giving rise to excessive siltation both within the area of the channel and outside it. Mr. Oxford, Jan de Nul’s managing director, said that it was not until March that Jan de Nul had conclusive evidence that the work as a whole was the cause of the siltation complained of, but in the face of the expert evidence it is impossible to accept that Jan de Nul responded to the evidence that was already available by early January 1997 in a way which could be expected of a reasonably prudent and careful contractor. Indeed, it was Royale Belge’s own case that Jan de Nul had not done so. I am satisfied, therefore, that Jan de Nul was negligent in failing properly to analyse the nature of the problem and to modify its methods of working so as to reduce the amount of new material put into suspension. 

24. In these circumstances I am satisfied that at several stages in the course of the preparation for and execution of the work Jan de Nul failed to take all reasonable care to ensure that its operations did not result in the deposit of excessive amounts of silt in areas outside the channel where it would interfere with adjacent land and with the activities of other users of the waterway. If Jan de Nul had carried out the investigations which in my view ought to have been undertaken, there is little doubt in my mind that it would have appreciated that its proposed method of working created a significant risk of widespread siltation. That could have been avoided to a significant extent, if not entirely, by cutting and loading the clay directly into barges in some areas and by restricting the period during which overspill was allowed to continue in others. 

 Negligence on the part of ABP 

25. Because Jan de Nul is seeking, in the alternative, to recover under the policy as the assignee of ABP, it is necessary to deal briefly with ABP’s position as well. I am reluctant to make findings of negligence against ABP because it is not itself a party to these proceedings and has had no opportunity to deal with the allegation. However, it is unnecessary for me to examine the question in detail or to make findings of that kind because Royale Belge was prepared to accept for present purposes that in relation to third parties who might be affected by the deposit of silt ABP’s position could not be distinguished from that of Jan de Nul. Accordingly, insofar as it may be relevant, I approach the question of ABP’s liability on the assumption that insofar as Jan de Nul was negligent towards third parties, ABP was negligent also. 

 Bases of liability 

26. Before turning to the position of the individual third party claimants it is convenient to deal in general terms with the principles of law governing liability in negligence, nuisance and public nuisance insofar as they relate to this case. 

 (a) Negligence 

27. As I have already indicated, the existence of a duty of care to other users of the estuary was not in dispute. The real debate between the parties turned on the nature of the loss and damage for which a wrongdoer in the position of Jan de Nul may be held liable in negligence. I am here concerned mainly with claims for damage caused by the deposit of silt on the bed of the river in sufficient quantities to interfere with navigation and the use of facilities such as slipways and moorings. Mr. Hamblen submitted that the only person who could claim for damage of that kind was the owner of the river bed. Except in the case of Marchwood military port which is owned by the Crown and Eling and Redbridge Marshes which are owned by the Hampshire Wildlife Trust, he submitted that none of the third parties who complained of siltation was the owner of the bed of the river in the affected area. With those two possible exceptions, therefore, all the claimants were seeking to recover purely economic loss resulting from damage to the property of a third party, a type of loss not recoverable in negligence. 

28. Mr. Schaff Q.C. recognised the force of this argument, but he submitted that private rights over property of the kind enjoyed by a lessee or licensee were also sufficient to support a claim in negligence so that those who were lessees of property which included part of the river bed as well as those who merely had a contractual right to occupy moorings were also entitled to recover. He also submitted that a statutory body such as ABP charged with a duty to maintain a navigable waterway had a sufficient interest to support an action in negligence against anyone who caused an obstruction to navigation in order to recover the cost of removing it. 

29. In the present case most of the third party claimants suffered some interference with the use of facilities situated on the bed of the river or adjacent to the waterway which either caused immediate financial loss or was likely to do so if the silt was not removed within a relatively short time. However, it is well established that in cases of this kind there is no liability in negligence for what is termed ‘pure’ economic loss, that is, financial loss resulting from damage caused to the property of a third party in which the claimant has some form of economic interest. This principle is established by a line of authority stretching from Cattle v Stockton Waterworks Co (1875) L.R. 10 Q.B. 453 to Leigh & Sillavan Ltd v Aliakmon Shipping Co. [1986] A.C. 785. Cases such as Candlewood Navigation Corporation Ltd v Mitsui OSK Lines Ltd [1986] A.C. 1 and Margarine Union GmbH v Cambay Prince SS Co. Ltd [1969] 1 Q.B. 219 make it clear that purely contractual rights in respect of the property which is damaged are not sufficient to support an action in negligence. The Candlewood case is of particular interest in that it concerned separate claims by the demise charterer and the time charterer of a vessel damaged in a collision and thus neatly illustrates the essential distinction. The demise charterer, who had a possessory interest in the vessel, was entitled to recover the cost of repairs and economic loss in the form of loss of hire while it was out of service. The time charterer, whose interest in the vessel was purely contractual, was unable to recover in respect of hire payable while the ship was out of service or his loss of profits. The authorities cited in support of that decision draw a clear distinction between those who have an interest in the property only as a result of contractual or other arrangements and those who have a proprietary or possessory interest in it: see [1986] A.C. at pages 15A-16D. The Privy Council in the Candlewood case declined to follow Caltex Oil (Australia) Pty v Dredge "Willemstad" (1976) 136 C.L.R. 529 to which Mr. Schaff also drew my attention. The decision in the Candlewood case was followed in The Aliakmon in which Lord Brandon at page 809 referred to 

 " . . . . . . . a long line of authority for a principle of law that, in order to enable a person to claim in negligence for loss caused to him by reason of loss of or damage to property, he must have had either the legal ownership of or a possessory title to the property concerned at the time when the loss or damage occurred, and it is not enough for him to have only had contractual rights in relation to such property which have been adversely affected by the loss of or damage to it." 

 The endorsement of this line of authority in The Aliakmon puts the position beyond doubt. I think that Mr. Hamblen was right, therefore, in saying that only those claimants who could show legal ownership or a possessory title to property damaged by siltation could pursue a claim in negligence. The position of ABP as conservator of the port raises rather different issues and is one to which I shall return at a later stage. 

 (b) Nuisance 

30. The tort of nuisance is concerned with unlawful interference with the use or enjoyment of land. Mr. Hamblen relied principally on two authorities, Tate & Lyle Industries Ltd v Greater London Council [1983] 2 A.C. 509 and Hunter v Canary Wharf Ltd [1997] A.C. 655, which, he submitted, ruled out the possibility of a claim in nuisance by any of the third parties other than the Crown in respect of Marchwood military port and Hampshire Wildlife Trust in respect of the Eling and Redbridge Marshes. 

31. Tate & Lyle v G.L.C. concerned a claim for interference with the use of two jetties caused by a build-up of silt in the river Thames following the construction of terminals for the Woolwich Ferry. With the permission of the Port of London Authority Tate & Lyle had constructed jetties on the bed of the river adjacent to its sugar refinery, but it did not enjoy any proprietary rights over the river bed and the jetties themselves were regarded as merely chattels. The House of Lords held that as a riparian owner Tate & Lyle was entitled to enjoy access to the water in contact with its frontage and to have the water flow to it in its natural state. However, although the siltation caused a reduction in the depth of water in the river, it did not interfere with these rights, nor did it pose any threat of damage to Tate & Lyle’s land. It merely impeded access to the jetties by vessels of a certain size. However, the House held that Tate & Lyle did not, by virtue of being a riparian owner, have any right to a minimum depth of water. Any remedy for interference with navigation in the river lay in public nuisance, not in negligence or private nuisance. 

32. In Hunter v Canary Wharf residents in the vicinity of Canary Wharf claimed damages for negligence and nuisance in respect of interference with the reception of television broadcasts caused by the construction of the tower block and in respect of the deposit of dust caused by the construction of a link road. The case is of interest for present purposes principally because the House of Lords considered the nature of the tort of private nuisance and the nature of the interest in land which is needed to support an action. Lord Goff pointed out at page 688E-G that an action of private nuisance will usually be brought by the person in actual possession of the land affected, either as the freeholder or tenant of the land in question, or even as a licensee with exclusive possession. He concluded, however, that although actual possession is sufficient to support an action, 

 "on the authorities as they stand, an action in private nuisance will only lie at the suit of a person who has a right to the land affected. Ordinarily, such a person can only sue if he has the right to exclusive possession of the land, such as a freeholder or tenant in possession, or even a licensee with exclusive possession . . . . . . . . But a mere licensee on the land has no right to sue." 

 Similar expressions of opinion can be found in the speech of Lord Lloyd and also in the speech of Lord Hoffmann who was at pains to point out that whatever form nuisance takes it involves an injury to land. The necessity for the claimant to have an interest in the land is therefore a critical factor when considering whether any of the third party claimants in the present case could have pursued an action in nuisance against Jan de Nul. 

33. Mr. Hamblen submitted that in a case such as the present a claimant would have to show that there had been negligence on the part of Jan de Nul in order to succeed in nuisance. Since I have found that Jan de Nul was negligent in the manner in which it carried out the work it is unnecessary for me to decide this question, but since it was fully argued, I propose to express my views on it shortly. 

34. Just over three years before the speeches were delivered in Hunter v Canary Wharf the nature of the tort of nuisance and its relationship to the tort of negligence and to the rule in Rylands v Fletcher had been considered by the House of Lords in Cambridge Water Co. v Eastern Counties Leather Plc [1994] 2 A.C. 264. The rule in Rylands v Fletcher is one of strict liability, but Lord Goff, with whom the other members of the Appellate Committee agreed, did not consider that it gave rise to a liability any more strict than that created by the law of nuisance. He said at page 299D: 

 "Of course, although liability for nuisance has generally been regarded as strict, at least in the case of a defendant who has been responsible for the creation of a nuisance, even so that liability has been kept under control by the principle of reasonable user - the principle of give and take as between neighbouring occupiers of land . . . . . . . . The effect is that, if the user is reasonable, the defendant will not be liable for consequent harm to his neighbour’s enjoyment of his land; but if the user is not reasonable, the defendant will be liable, even though he may have exercised reasonable care and skill to avoid it." 

35. Lord Goff then turned to the question of foreseeability of damage as a necessary element in liability for nuisance. He dealt with the point in the following way at page 300E-G: 

 "We are concerned with the liability of a person where a nuisance has been created by one for whose actions he is responsible. Here, as I have said, it is still the law that the fact that the defendant has taken all reasonable care will not of itself exonerate him from liability, the relevant control mechanism being found within the principle of reasonable user. But it by no means follows that the defendant should be held liable for damage of a type which he could not reasonably foresee; and the development of the law of negligence in the past 60 years points strongly towards a requirement that such foreseeability should be a prerequisite of liability in damages for nuisance, as it is of liability in negligence." 

 And later, at page 301C, having referred to the passage in The Wagon Mound (No.2) [1967] 1 A.C. 617, 640 in which the Privy Council held that foreseeability of damage is a necessary element in determining liability in all cases of nuisance, he said 

 "It is widely accepted that this conclusion, although not essential to the decision of the particular case, has nevertheless settled the law to the effect that foreseeability of harm is indeed a prerequisite of the recovery of damages in private nuisance, as in the case of public nuisance. . . . . . . . . It is unnecessary in the present case to consider the precise nature of this principle; but it appears from Lord Reid’s statement of the law that he regarded it essentially as one relating to remoteness of damage." 

36. These passages from the speech of Lord Goff point clearly to the conclusion that although foreseeability of damage is a prerequisite of the recovery of damages in private nuisance, negligence in the creation of the nuisance is not an essential element of liability. The essential control mechanism is reasonable user as between neighbouring occupiers of land, but what constitutes reasonable user must depend on the circumstances of the case. Although the work in the present case can be said to have been undertaken for the public benefit, I do not think that capital dredging on the scale undertaken here which resulted in the deposit of substantial quantities of silt on neighbouring properties was a reasonable user of the land in question, especially when the consequences of carrying out the work in the chosen manner were reasonably foreseeable. Accordingly, I would hold that all the elements of the tort of nuisance could have been made out by those who had sufficient interest in the areas affected, even if Jan de Nul had taken all reasonable precautions to avoid such damage. 

 (c) Public Nuisance 

37. Public nuisance is a wide-ranging concept. First and foremost it is an offence at common law which consists in doing an act not warranted by law, or failing to discharge a duty imposed by law, the effect of which is to endanger the life, health, property, morals or comfort of the public, or to obstruct the public in the exercise or enjoyment of rights common to the public at large: see R v Shamrock [1994] Q.B. 279, 283 (C.A.) approving statements of principle to be found in Attorney-General v P.Y.A. Quarries Ltd [1957] 2 Q.B. 169 and earlier authorities. It follows that a person who unlawfully obstructs the exercise of rights enjoyed by the public at large commits a public nuisance. One of the most common modern examples is obstruction of the highway over which all members of the public have a right to pass and repass. It is because such acts or omissions affect the public at large that they are punishable as offences at common law and are actionable at the suit of the Attorney-General on behalf of the public. For similar reasons a public nuisance is actionable as a tort at the suit of an individual only if he has suffered particular damage over and above the general inconvenience suffered by the public as a whole. In Attorney-General v P.Y.A. Quarries the court was concerned with the impact on the local community of blasting operations carried on by the defendant in the course of its quarrying activities. When the matter reached the Court of Appeal the main issue in the case was whether a sufficient number of people were affected to constitute a class of the public. Denning L.J. said at page 191 

 "A public nuisance is a nuisance which is so widespread in its range or so indiscriminate in its effect that it would not be reasonable to expect one person to take proceedings on his own responsibility to put a stop to it but that it should be taken on the responsibility of the community at large. Take the blocking up of a public highway or the non-repair of it. It may be a footpath very little used except by one or two householders. Nevertheless, the obstruction affects everyone indiscriminately who may wish to walk along it." 

 The court held that whether a class of the public is affected is a question of fact in each case. That case is very different from the present, but Denning L.J.’s comment is of interest because it illustrates the fact that interference with the public right to use the highway (and the same must be true of the public right to use a navigable waterway) constitutes a public nuisance because it affects everyone’s right in the same way, even though in practice that right is exercised by a small number of people. 

38. In the present case it was common ground that there is a public right of navigation throughout the tidal waters of the estuary. Any significant interference with the right of navigation caused by the deposit of silt would therefore constitute a public nuisance: see Tate & Lyle v G.L.C. at page 537. The facts of that case are of some interest. The extent of the siltation was sufficient to obstruct access to Tate & Lyle’s jetties by vessels of the requisite dimensions, but there is nothing to indicate that it was sufficient to obstruct navigation in the river generally. Nonetheless, that degree of obstruction was sufficient to constitute a public nuisance, and the damage suffered by Tate & Lyle was sufficient to entitle it to recover damages. In the case of the raw sugar berth, which together with its approach channel had been created by dredging, the House held that once the dredged channel and berth had been created the public right of navigation extended over them to their full depth. 

39. Mr. Hamblen submitted that not every obstruction of a highway or waterway will constitute a public nuisance; there must be a substantial interference with the ability to exercise the public right of passage or navigation. In support of this submission he referred me to R v Betts and others (1850) 16 Q.B. 1022, a case which concerned a trial on indictment for public nuisance. The indictment contained six counts, one of which alleged that the defendants had caused a public nuisance by constructing a bridge over the river Witham which obstructed navigation by reason of the fact that one of its piers occupied part of the river bed. The jury took the view, however, that the bridge was not an obstruction to navigation and found the defendants not guilty. On a motion to enter a verdict for the defendants the court held that the river was a public highway, but that it was for the jury to decide whether in fact the bridge constituted an obstruction. 

40. I have to say that I do not obtain a great deal of assistance from that case. Insofar as it decides that the existence of an obstruction to navigation is a question of fact, I find it unsurprising and it does not contain any further statement of principle which assists in the determination of the present case. In particular, I do not think that it provides any useful guidance on the question of what degree of obstruction of the right of navigation is necessary to constitute a public nuisance, and could hardly do so. That must be a matter to be determined on the facts of the individual case. 

41. Mr. Hamblen submitted that the siltation in the present case did not sufficiently affect the public at large to constitute a public nuisance. I am unable to accept that. The public had a right of navigation over the whole of the estuary and the passage in the judgment of Denning L.J. in Attorney-General v P.Y.A. Quarries to which I have referred, as well as the decision of the House of Lords in Tate & Lyle v G.L.C., makes it clear that where there is physical interference with a right of that kind the fact that it is actually exercised by very few members of the public does not prevent the obstruction from constituting a public nuisance. This is further illustrated by the case of Walsh v Ervin [1952] V.L.R. 361 to which I shall come in more detail in a moment. In the present case access to certain parts of the estuary was significantly affected by the deposit of silt and I am quite satisfied that there was in those areas a substantial interference with the public right of navigation. 

42. It is well established that in order for a private individual to maintain an action for damages for public nuisance he must be able to show that he has suffered damage over and above that suffered by the public generally. In Benjamin v Storr (1874) L.R. 9 C.P. 400 the plaintiff’s coffee house was badly affected by the defendant’s wagons standing for long periods in the narrow street outside for the purposes of loading and unloading goods. The wagons blocked his light and the frequent staleing of the horses detracted from his enjoyment of his dwelling. Brett J. put the matter in this way (page 406): 

 "The cases referred to upon this subject shew that there are three things which the plaintiff must substantiate, beyond the existence of the mere public nuisance, before he can be entitled to recover. In the first place, he must shew a particular injury to himself beyond that which is suffered by the rest of the public. It is not enough for him to shew that he suffers the same inconvenience in the use of the highway as other people do, if the alleged nuisance be the obstruction of a highway. . . . . . . . . Other cases shew that the injury to the individual must be direct, and not a mere consequential injury; as, where one way is obstructed, but another (though possibly less convenient one) is left open; in such a case the private and particular injury has been held not to be sufficiently direct to give a cause of action. Further, the injury must be shewn to be of a substantial character, not fleeting or evanescent." 

43. That case is unusual in that the plaintiff was not really complaining of the obstruction of the highway as such but of the fact that the way in which the defendant chose to employ his wagons interfered with the use and enjoyment of his premises. The injury which he suffered was quite different from that suffered by the public at large and was both direct and substantial. In practical terms it was tantamount to a private nuisance. However, the principle stated by Brett J. has been applied in many subsequent cases and Mr. Hamblen submitted that even if some people experienced difficulty in obtaining access to or using their moorings because of the deposits of silt, they did not suffer a sufficiently direct or substantial injury to support an action in public nuisance. In support of this argument he drew my attention to Martin v London County Council (1898) 14 T.L.R. 575 in which the plaintiff complained of the obstruction for several months of the street in which he carried on business while road improvements were being carried out in the area. It was still possible to gain access to his shop, but only by a roundabout route, and he complained of a loss of custom as a result. Applying the principle stated by Brett J. in Benjamin v Storr the court dismissed the plaintiff’s claim on the ground that he could not show that he had been injured specially and directly. This strikes me as a rather hard decision because when one is concerned with obstruction of the highway it must rarely be the case that no alternative route is available. However, the decision is no more than one example of the operation of the rule in practice. In the end the question whether the plaintiff’s injury is sufficiently "special" and "direct" must depend very much on the facts of the case. 

44. In Walsh v Ervin [1952] V.L.R. 361 the plaintiff and defendant were farmers holding land on opposite sides of the highway. The defendant had placed obstructions on the road and had ploughed part of it thereby obstructing the plaintiff’s access to that stretch of the road from his property by vehicle for a period of some three years and preventing his use of the highway. One question which arose for determination was whether the plaintiff had a personal right of action in public nuisance to obtain an injunction and damages even though he could not prove any actual pecuniary loss capable of being precisely ascertained in money terms. For that purpose it was necessary to decide whether he had suffered special or particular damage sufficient to support an action in public nuisance. The plaintiff used the road in order to gain access to the main roads in the area. Over a period of about 15 months he was obliged on about a dozen occasions to take sheep between his home block and another piece of land by a more circuitous route which involved a substantial loss of time. Sholl J. reviewed the authorities stretching back over 400 years in which he noted that different views had been expressed at different times as to whether enforced diversion could amount to particular injury of a direct nature. He concluded at page 369 that 

"delay and inconvenience of a substantial character, direct and not merely consequential, so long as not merely similar in nature and extent to that in fact suffered by the rest of the public, may amount to sufficient damage, particular to the individual plaintiff, notwithstanding that, in another sense, it is "general" and not "special" damage to him." 

The valuable analysis of the earlier authorities carried out by Sholl J. supports the conclusion that an individual may pursue an action based on a public nuisance if he has suffered some substantial, that is, more than merely trivial, injury over and above that suffered by the public at large. Whether the plaintiff has suffered such an injury is essentially a matter of fact, but in the present case the injury suffered by the public at large is limited to the interference with the freedom of navigation in the estuary generally. In those circumstances any significant interference with an individual’s commercial operations or the enjoyment of private rights resulting from the obstruction to navigation would in my judgment represent damage over and above that suffered by the public at large and would be sufficient to support an action. 

Damages 

45. Jan de Nul has sought to quantify its claim in these proceedings by reference to the expenses incurred in carrying out remedial works on the grounds that they fairly reflect the measure of the liability which it incurred to the various third party claimants. However, as Mr. Hamblen rightly pointed out, none of those affected by the siltation, apart from the fishermen, put forward a quantified claim for damages. That, he submitted, strongly suggested that the siltation had not in fact caused any real loss. He also submitted that any loss which had been suffered was in reality very modest and that such amounts as would have been recoverable in damages fell far short of the costs incurred in carrying out the remedial work. The remedial work did not, therefore, represent a reasonable response to the situation and the amount of the claim did not reasonably reflect the true extent of Jan de Nul’s liability. 

46. Before turning to these questions it is necessary to say something about the evidence relating to the claims made by the various third parties. This is mainly to be found in the correspondence passing between them and ABP to whom they naturally directed their complaints. It was, of course, open to Jan de Nul to obtain evidence for the purposes of the trial from the third parties describing the nature of the siltation and its effect on their operations and that evidence could have been put before the court by calling witnesses or in written form. However, in the belief that this was not a matter of great controversy and in an attempt to save costs Jan de Nul invited Royale Belge at the pre-trial review to say whether it challenged the substance of the evidence contained in the disclosed correspondence. Royale Belge responded by saying that it accepted the substance of the evidence, but did not accept that, as a matter of law, it established that Jan de Nul was liable to the claimants "in private nuisance or negligence (or otherwise)". In the light of that reaction Jan de Nul decided to rely at trial simply on the correspondence. 

47. In the course of his submissions Mr. Hamblen was critical of the state of Jan de Nul’s evidence relating to the position of many of the third parties. He submitted that there was little satisfactory evidence of the arrangements under which some of them occupied their premises or of the damage which they suffered as a result of the siltation. In some respects these criticisms are well-founded, but wherever there are apparently reliable statements in the correspondence relating to these matters I think it right to accept the evidence at face value. A more critical approach might well have been appropriate if Royale Belge had taken a different stance in relation to the correspondence. As it is, having formally accepted the substance of what is stated in the correspondence it cannot now invite the court to take a different approach. 

48. The fact that none of the third parties apart from the fishermen put forward a claim for specific loss raises the question whether damages may be recovered by a person whose rights have been infringed but who is unable to calculate with any precision in money terms the amount of his loss. Mr. Hamblen submitted that damages could not be awarded in such circumstances, or at any rate not to commercial claimants who could have no enjoyment of the amenity value of the property they occupied. However, I am unable to accept that that is correct. It is well established that damages may in general be awarded for the infringement of private rights even where the effects of the infringement cannot be assessed with any precision in monetary terms. Usually this arises in cases where the nature of the damage is such as to be inherently unquantifiable in monetary terms, but I do not think that it is limited to such cases. In Hunter v Canary Wharf Lord Hoffmann, commenting on Bone v Seal [1975] 1 W.L.R. 797 (a case concerning nuisance by noxious smells), said at page 706D 

 "In that case it was said that "efforts to prove diminution in the value of the property as a result of this persistent smell over the years failed." 

I take this to mean that it had not been shown that the property would sell for less. But diminution in capital value is not the only measure of loss. It seems to me that the value of the right to occupy a house which smells of pigs must be less than the value of the occupation of an equivalent house which does not. In the case of a transitory nuisance, the capital value of the property will seldom be reduced. But the owner or occupier is entitled to compensation for the diminution in the amenity value of the property during the period for which the nuisance persisted. To some extent this involves placing a value on intangibles. But estate agents do this all the time." 

 Lord Hoffmann was there speaking in the context of a claim in private nuisance and the award of general damages for loss of enjoyment of private property, but the principle that general damages may be awarded where an injury has been suffered which cannot be precisely measured in monetary terms is of general application. It is, after all, the basis on which damages are awarded for pain and suffering in an action for negligence causing personal injury and the same principle can apply in other situations in which an infringement of rights has caused damage of a kind which is not susceptible to precise quantification in money terms. I see no difficulty in applying this principle in a proper case where liability arises in nuisance or negligence. Public nuisance raises different considerations only in the fact that the claimant must be able to show that he has suffered damage over and above that suffered by the public generally. However, once he can show that he has suffered some direct and substantial injury over and above that suffered by the public at large I can see no reason in principle why the court should not be able to award general damages in respect of it and I respectfully agree with Sholl J. for the reasons he gives in Walsh v Ervin that the authorities do not preclude it from doing so. This is also the view taken by the editors of the current (17th) edition of Clerk & Lindsell on Torts (paragraph 18-94). On the other hand in the case of a commercial organisation the amount awarded is unlikely to be substantial in the absence of proof of specific loss. 

49. Mr. Hamblen’s second point, namely, that the remedial dredging did not represent a reasonable response to the situation and that the cost which it entailed did not reasonably reflect the extent of the liability incurred towards the third parties, is of a rather different nature and is one to which I shall return when I come to consider the position of the individual claimants. However, there are some matters of general relevance which it is worth mentioning at this stage. First, the measure of damages in the case of torts affecting land. I would accept Mr. Hamblen’s submission that the starting point for damages in such cases is the reduction in the value of the land, but that is only a starting point. Consequential loss is also recoverable and in many cases the cost of reinstatement may be recovered if it is reasonable to reinstate the land: see McGregor on Damages, 16th ed. paragraphs 1392-1397. In Hunter v Canary Wharf Lord Lloyd said at page 695D-E that 

"the diminution in the value of the land will usually (though not always) be equal to the cost of reinstatement" (my emphasis). 

Another point to be borne in mind is that ABP as conservator of the port had an interest in maintaining the facilities of the port and a duty to ensure that it remained safe for ordinary navigation. There is nothing to suggest that any of the silt would have dispersed naturally; on the contrary, the evidence is that over the course of time it would have tended to consolidate. In general, therefore, I think Mr. Schaff was right in saying that it is unrealistic to suggest that no action at all should have been taken and it is not entirely surprising that quantified claims were not pressed given that ABP took action to begin clearing silt from most of the affected areas during the early summer of 1997. I do not think that it would be right to assume that no claims would have been pursued even if remedial action had not been taken. I think it is also significant that at no stage did Mr. Sainderichin or Mr. De Keyser suggest that the steps which ABP had taken or which Jan de Nul proposed to take were unreasonable. Jan de Nul was bound by clause 27.3 of the General Conditions to take all reasonable steps to mitigate the consequences of a loss and I would accept that its right to recover expenses incurred for that purpose depends on the reasonableness of its response to the situation: see the comments of Eveleigh L.J. in Integrated Container Service Inc v British Traders Insurance Co. Ltd [1984] 1 Lloyd’s Rep. 154 at page 158. Although it was undoubtedly difficult to assess exactly what losses the third party claimants would suffer if the silt were not removed, I am satisfied that in general it was reasonable for ABP and Jan de Nul to incur the cost of the remedial work. Such indications as there are suggest that the cost of employing another contractor to remove the silt would have exceeded the cost incurred by Jan de Nul using its own equipment. 

The position of the individual third party claimants 

48. With these points in mind it is convenient to return to the position of the individual third party claimants. 

49.(i) The Ministry of Defence - Marchwood military port. It was common ground that the Crown is the owner and occupier of the river bed in the area of Marchwood military port. As such it had sufficient interest to make a claim in negligence and private nuisance. Soundings taken by ABP in June 1997 indicated that the depth of water in the area of the military port had been reduced by up to 2m. with consequent interference with the approaches to the port and the use of berths. I am satisfied that the degree of interference was sufficient to require remedial dredging in order to keep the port fully operational. In these circumstances the Ministry of Defence on behalf of the Crown had a good claim against Jan de Nul in negligence and nuisance. It is unnecessary in these circumstances to decide whether there was a public right of navigation within Marchwood military port. 

50. ABP and Jan de Nul between them incurred costs of £509,797.67 in carrying out remedial work in this area. Mr. Hamblen submitted that there was little evidence of actual interference with the operation of the port and that the Crown would not have recovered approaching that amount in damages. At first sight there appears to be some force in this point, but there is evidence that some vessels were unable to berth at nominated berths and that silt was interfering with the boat lift. ABP’s own survey indicated that the depth of water had been reduced by as much as 2m. If ABP had refused to take any action I have little doubt that it would have been reasonable for the Crown to take measures to ensure that the port remained fully operational and that it would have done so. It would then have been entitled to recover the cost of doing so. Despite the magnitude of the sum involved I think that the costs incurred by ABP and Jan de Nul to restore the depth of water in this area were reasonable. 

51.(ii)(a) Southern Water Services - Slowhill Copse. Southern Water made use of a berth at Slowhill Copse for the transport of waste water sludge. Siltation in the area of the berth caused a reduction in the depth of -water of 1-2m. which interfered with its use. The berth at Slowhill Copse together with a dredged channel connecting it to the main shipping channel was constructed by Southern Water under the terms of a deed dated 6th June 1980 by which ABP granted it certain rights for a period of 50 years over 8.4 acres of land forming part of the river bank and foreshore. Viewing it as a whole, I think that this deed was effective to grant Southern Water exclusive possession of the land to which it relates. The plan attached to the deed is difficult to read, but appears to show that the land subject to the grant extends from the creek out to the line of the main shipping channel. I think it likely, therefore, that Southern Water was in possession and occupation of most, if not all, of the area affected by the siltation and so had sufficient interest to claim in negligence and nuisance. 

52. The costs incurred in removing silt obstructing the use of the berth at Slowhill Copse was £68,894.42. Mr. Hamblen submitted that there was no evidence of an existing obstruction to vessels using the berth, merely a suggestion that difficulties were likely to be encountered at some future date, and that partly due to the effects of natural siltation. However, there is sufficient evidence that the deposit of silt adversely affected this berth and where there is liability in negligence and nuisance it is no answer to say that dredging would have been required at some time in the future in any event. I am satisfied that it was reasonable for Jan de Nul to incur these costs in carrying out remedial work. 

53.(ii)(b) Southern Water Services - Weston jetty Southern Water also made use of two berths at Weston jetty on the Itchen. The position in relation to these berths is rather different. At some time prior to 1980 (the precise date is unclear) Southern Water purchased Weston jetty from Southampton City Council to enable waste water sludge to be loaded by pipeline. There is nothing before me to suggest that in this case it obtained any rights or interest in the bed of the river on which the jetty stands. In relation to the berths at this jetty the position of Southern Water appears to be substantially the same as that of Tate & Lyle in relation to its sugar jetties. In the absence of any physical damage to the jetty, no claim could have been made in negligence because the loss suffered by Southern Water was purely economic. Nor would a claim lie in private nuisance since Southern Water has no interest in the land on which the silt was deposited. Mr. Hamblen submitted that, as in the case of Slowhill Copse, there was no satisfactory evidence of any interference with the use of the jetty and therefore no obstruction of the public right of navigation, but I am unable to accept that. The correspondence between Southern Water and ABP shows that the masters of the two vessels which used the berth had experienced difficulties there, even though it was still possible to use it. The interference with the right of navigation may not have been substantial, but I am satisfied that it existed nonetheless. In substance I think that the position with regard to Weston jetty is indistinguishable from that which existed in the Tate & Lyle case. Here too there was an obstruction of the public right of navigation as a result of which Southern Water suffered particular damage. 

54. The costs incurred in removing silt from the area of Weston jetty was the relatively modest amount of £14,281.16. If no steps had been taken to remove the silt I think it very likely that there would have been serious interference with the use of the jetty as natural siltation further reduced the depth of water. At that point I have no doubt that a formal claim would have been made and steps would have had to be taken to remedy the situation. In those circumstances I am satisfied that it was reasonable to incur the costs of removing the siltation. 

55.(iii) Marchwood Wharfage Ltd The company carried on a commercial wharfage business at the Marchwood wharf where the siltation resulted in a reduction of up to 3m. in the depth of water available in the approaches and areas adjacent to the berth. There is, however, no evidence of the basis on which the company occupied the wharf at the relevant time. In these circumstances Mr. Schaff was constrained to accept that any claim it might have would lie in public nuisance only. 

56. Mr. Hamblen submitted that there was little evidence of any actual interference with the use of the berth. Marchwood Wharf made its first complaint to ABP in March 1997 when it first noticed the arrival of the silt. At that stage it simply warned ABP that there was a risk that siltation would interfere with access to and flotation at the berth and indeed there is evidence in the correspondence between ABP and Jan de Nul that the depth of clear water in that area had been reduced by as much as 3m. It is quite true that Marchwood Wharf never did assert that any vessels had been unable to use the berth, but one reason for that may have been the fact that ABP carried out remedial dredging in that area during May 1997. It is difficult to know exactly what would have happened if no steps had been taken to deal with the problem, but the evidence indicates that there was a substantial amount of silt present and I think it likely that as it consolidated it would have presented an obstruction to the use of the berth. 

57. If I am right in thinking that the siltation was or would eventually have become an obstruction to navigation in that part of the port, there is nothing to distinguish the position of Marchwood Wharfage from that of the plaintiffs in the Tate & Lyle case. If no steps had been taken to remove the silt it is likely that sooner or later there would have been a significant interference with its business. The costs incurred in removing the silt amounted to £46,426.80 which does not appear to me to be unreasonable in that context. 

58.(iv) Husband’s Shipyards Ltd In March 1997 Husband’s complained of a build-up of silt which was interfering with its berths, slipways and moorings. There is no evidence of the precise extent to which the depth of water was reduced, but it was sufficient for the Engineer to give instructions to Jan de Nul to carry out remedial dredging in that area and on the evidence as a whole I am satisfied that it was sufficient to interfere significantly with the company’s operations. The evidence of the basis on which Husband’s occupied its premises at Cracknore Hard is not entirely satisfactory. However, correspondence between the company’s solicitors, Heppenstalls, and ABP in September 1991 indicates that Husband’s occupied the premises under a lease from the Crown of 17th July 1956 covering 18.4 acres of the river bed below high water mark "together with a jetty, four slipways, two boat building sheds, two dolphins and four piles erected thereon". (I quote from Heppenstalls’ letter of 25th September 1991 in which they quote the terms of the lease.) I have not seen a copy of the lease in question, but in the light of what I said earlier about this evidence I think it is sufficient to justify my finding that Husband’s was in possession of that part of the foreshore on which it carried on business and so had sufficient title to support a claim in negligence and nuisance. 

59. The total costs incurred in removing silt from this area was £109,303.85. Again, it is right to say that no claim for damages was ever put forward by Husband’s, but, as in the case of Marchwood Wharfage, that is almost certainly because ABP took steps to alleviate the problem at an early stage. The slipways were cleared in June 1997 and a certain amount of dredging was undertaken by ABP between May and September of that year. There can be little doubt on the evidence that if nothing had been done the silt would have had a significant continuing impact on Husband’s business which would have led in turn to a substantial claim. As in most of these cases, taking no action was not a prudent or practical option and I am satisfied that it was reasonable to incur the costs of removing the silt. 

60.(v) and (vi) Marchwood Yacht Club and owners of private moorings Marchwood Yacht Club occupies a piece of land on the south-western side of the estuary near the top of the Upper Swinging Ground. The club complained as early as January 1997 that its mooring area and slipway were being adversely affected by siltation and a survey confirmed that there was up to 0.5-0.6m. depth of silt in some areas. A subsequent survey established that there was "a massive amount" of siltation sufficient to cause some areas of the mooring ground to dry out at low water for the first time. The yacht club was in occupation of the slipway and had obtained the right to place 138 moorings in a designated area of the river bed within the Marchwood Basin for the use of club members under a licence granted by ABP for which it paid an annual fee. Similar licences were granted to a number of individual owners to place moorings and to moor boats at various locations in the same general area. 

61. As occupier of the slipway the yacht club had a sufficient interest to claim damages in negligence and nuisance in respect of its obstruction by silt, but the damages flowing from that are insignificant. Much more important for present purposes is the obstruction of the moorings. Mr. Schaff submitted that the licences granted by ABP conferred private rights on the club and the individual owners which were sufficient to support claims in nuisance. In support of that argument he relied on the decision in Crown River Cruises Ltd v Kimbolton Fireworks Ltd and another [1996] 2 Lloyd’s Rep. 533. In that case a barge permanently moored in the river Thames was damaged by fire as a result of a firework display. Potter J. held that the owner’s right to exclusive use and occupation of the mooring was sufficient to support an action in nuisance. 

62. The most recent discussion of this question, as well as the most authoritative, is now to be found in Hunter v Canary Wharf, the speeches in which were delivered some 14 months after the judgment in the Crown River Cruises case. It is clear from the speeches in Hunter that nuisance is a tort affecting the use and enjoyment of land and therefore to support a claim in nuisance a person must have an interest in land. Normally legal ownership or a right to exclusive possession is necessary, although an easement or profit will also suffice for such a claim - see, for example, per Lord Hoffmann at page 702G-H. However, the mooring licences granted by ABP in the present case did not purport to grant an interest in the land forming the river bed; they merely granted permission to put down a mooring. Indeed, they provided in terms that they could be cancelled by ABP at any time. Accordingly, whatever may have been the position in Crown River Cruises v Kimbolton Fireworks, I do not think that any of the licensees in the present case were owners of rights in the nature of an easement or held a sufficient interest in the river bed to entitle them to claim either in negligence or in nuisance. The position here is very different from that which obtained in Booth v Ratté (1890) 15 App. Cas. 188 (P.C.), one of the authorities relied on in the Crown River Cruises case. In that case the plaintiff was the legal owner of the river bank to which his floating boathouse and wharf were moored and was also owner, or at any rate was in possession, of that part of the river bed in the area where they were moored. None of those conditions existed in the present case. Nonetheless, the siltation undoubtedly interfered at certain times of the tide with navigation throughout the Marchwood Basin and those who were prevented from reaching or leaving their moorings or the yacht club slipway at certain times of the tide suffered damage beyond that suffered by the public at large. In my judgment, therefore, they were entitled to make a claim in public nuisance. 

63. The costs incurred in carrying out remedial work in the area of the moorings amounted in all to £728,686.50. (A further sum of £641,656.71 was incurred in removing silt from the general area of the Marchwood Basin). This is a very substantial sum and explicable only by the fact that a large area was involved which was heavily affected. Mr. Hamblen submitted that it far outweighed any amounts which the yacht club and private owners of moorings could have expected to recover by way of damages in an action against Jan de Nul and he relied on the fact that the moorings were relocated, albeit temporarily, without any obvious complaints. He suggested that the owners could not really ask for anything more. 

64. The evidence does not enable me to say with certainty how many mooring owners were affected altogether, but even if the number were as high as 250 the expenses incurred in dredging the area of the moorings alone would represent something over £2,900 each which is a substantial sum by comparison with the annual mooring fee of £64. On the other hand, it is necessary to bear in mind that for the yacht club itself (and perhaps also for some of the private mooring owners) it was highly desirable, if not essential, for moorings to be located in reasonable proximity to the club buildings and slipway. Simply to have left the silt where it was, therefore, could have had a serious effect on the club’s activities. Even so, if this part of Jan de Nul’s claim rested solely on its liability to the yacht club and the mooring owners there would be room for the argument that the sum was not a reasonable reflection of its liability to these claimants. However, the area in which the moorings lay formed part of the general area of the Marchwood Basin in which rights of navigation were generally affected by the deposit of silt and therefore other factors have to be taken into consideration which it is convenient to consider in the context of the work carried out in the Marchwood Channel and Basin. 

65.(vii) ABP and others in respect of obstruction of the Marchwood Channel and Basin. A chart of the port prepared by ABP in November 1997 (the accuracy of which was not challenged) shows that it owned the river bed in way of the Marchwood Channel and about half of the river bed underlying the rest of the Marchwood Basin. That would be sufficient to support a claim in negligence and nuisance in respect of the deposit of silt in those areas, but there is no evidence that ABP as owner of the river bed suffered any significant damage as a result of the siltation and it did not have a similar interest in the river bed underlying the remainder of the Marchwood Basin. However, I think Mr. Schaff was right in submitting that as conservator of the port ABP had a sufficient interest in the maintenance of the port to recover in negligence the cost of removing obstructions to navigation in accordance with the principles stated in Dee Conservancy Board v McConnell [1928] 2 K.B. 159, to which I shall refer more fully later. Although it is fair to say that this ground of liability did not receive much attention until the later stages of the hearing, it was fully argued before me and is one on which I think Jan de Nul should be allowed to rely. It does, of course, raise the question whether the degree of siltation in the Marchwood Channel and Basin generally was such as to constitute an obstruction to navigation and whether it was reasonable for ABP as conservator of the port to remove it, and to that extent it raises issues of fact, but these were live issues in any event. In my view the evidence adduced in relation to the yacht club, Marchwood Wharfage and Husband’s Shipyard amply bears out the contention that the degree of siltation in this area of the port was such that it did constitute an obstruction to navigation and could not simply be left as it was. In my judgment it was reasonable for ABP to take steps to restore the original depth of water in this area. 

66.(viii) ABP in respect of interference with berths 30-36. These berths which lie in the Itchen approaches are constructed on land owned by the Crown, but were occupied by ABP as the statutory authority responsible for operating the port of Southampton. As a result of the dredging work silt was deposited in these berths and in the Itchen approaches in sufficient quantities to reduce the depth of water to below the advertised minimum and to interfere with normal commercial operations. The Harbour Master was adamant that advertised depths had to be restored in order to allow unrestricted access of normal commercial traffic and it is difficult to see that taking no action was a practical option. In the event some dredging was carried out in this area by ABP itself in May, August and September 1997 and by Jan de Nul in June and July. The fact that these operations were carried out at an early stage explains why no claim for consequential losses was put forward. As in other cases Mr. Hamblen submitted that it was unreasonable to incur costs of this magnitude in carrying out remedial work, but I do not think that there was any practical alternative. Any significant restriction in the depth of water in the Itchen approaches would be likely to have serious commercial implications for a busy port of this kind. I am satisfied, therefore, that it was reasonable to incur these costs in order to restore the original depth of water. In my view ABP was entitled to recover the cost of removing silt from these areas in its capacity as conservator of the port. 

67.(ix) Waterside Fisherman’s Association The fishermen’s association acted as spokesman for those who exploited the clam and oyster beds in various parts of Southampton Water on a commercial scale. Its claim was eventually settled by a payment of £27,400.37. There was no complaint of interference with the public right of navigation in the fishing grounds, but it is said that there was an interference with the public right of fishing. A survey carried out by ABP’s research department in June 1997 indicates that clam and oyster beds in different parts of the estuary were affected to varying degrees. In the Dibden Bay area the dredging works caused severe damage to the shellfish beds by smothering them with a deep layer of silt, thereby destroying a substantial part of the stock. Mr. Schaff accepted that none of the fishermen enjoyed any private right to fish in the waters affected by silt deposits; they were simply entitled to exercise a right which is enjoyed by the public at large. Their claim, if they had one, must therefore have been in public nuisance, but Mr. Hamblen submitted that an interference with the public right of fishing did not constitute a public nuisance, and that even if it did, the fishermen suffered no particular loss over and above other members of the public such as would entitle them to make a claim on that ground. 

68. Questions of a very similar kind arose for consideration in Australia in Ball v Consolidated Rutile Ltd [1991] Qd. Rep. 524 where the slippage of a sand dune into Moreton Bay adversely affected the operations of commercial prawn fishermen. The sand dune carried with it into the bay a large number of trees and amounts of other vegetation, some of which was carried by the current into areas where the plaintiffs fished for prawns. These obstructions interfered with the use of nets and made fishing in that area uneconomical as a commercial activity. As a result the plaintiffs lost catches of prawns which they would otherwise have made. Ambrose J., having considered a number of Canadian authorities and the decision of the Privy Council in Attorney-General for British Columbia v Attorney-General for Canada [1914] A.C. 153 declined to hold in the absence of binding authority that an interference with the right to fish in tidal waters constituted a public nuisance, although a contrary conclusion had been reached in Canada: see Hickey v Electric Reduction Co. of Canada Ltd (1970) 21 D.L.R. (3d) 371. 

69. The nature of the public right to fish in tidal waters is a right to take fish, including shellfish, by whatever means are considered effective, subject to any statutory restrictions: see Attorney-General for British Columbia v Attorney-General for Canada at page 169 approving in general terms the passage in Hale’s De Jure Maris cited by Lord Blackburn in Neill v. Duke of Devonshire (1882) 8 App. Cas. 135. While I would agree with Ambrose J.’s analysis of the decision in Attorney-General for British Columbia v Attorney-General for Canada, I would respectfully differ from him on the question of whether an interference with the right to fish is capable of constituting a public nuisance. The concept of public nuisance is, as I have already observed, very wide and in my view is as capable of embracing damage to stocks of fish to which the public at large has a right to resort as it is to the interference with the right of navigation or the enjoyment of other rights. In the case of a private fishery damage to the fish by polluting the water gives a right of action for interference with the owner’s rights: see Nicholls v Ely Beet Sugar Factory [1936] 1 Ch. 343. There are obvious differences, of course, between the rights represented by a private fishery and the public right to fish in tidal waters, but I think there is a sufficient similarity between them to support the conclusion that an act which damages stocks of fish to which the public has access is capable of constituting a public nuisance. I can see that in general it is likely to be difficult to show that in tidal waters any particular stocks of fish were available for exploitation by the public, but in the case of shellfish such as clams and oysters that difficulty largely disappears. In the absence of authority to the contrary, therefore, I am of the view that damage to established shellfish beds of the kind which occurred in the present case is capable of constituting a public nuisance. 

70. Ambrose J. in Ball v Consolidated Rutile Ltd also held that even if interference with the public right of fishing could constitute a public nuisance, the deposit of material in fishing grounds which made it more difficult to catch fish by using certain types of gear was not sufficient to do so, and that in any event the economic loss suffered by the plaintiffs did not represent particular damage such as would entitle them to maintain an action. He did so on the grounds that the economic loss which the plaintiffs suffered by being unable to fish in certain parts of Moreton Bay was loss of a kind common to all the commercial fishermen who wished to trawl those areas. I do not myself think that the fact that several people may have suffered in a similar manner prevents them from making a claim of this kind, but whether the claimant in any case has suffered particular damage is in my judgment essentially a matter of fact in each case. In Tate & Lyle v G.L.C. the plaintiff was held to have suffered particular damage because access to its jetties was impeded. In the present case the damage which the fishermen suffered as a result of the siltation of the shellfish beds was in one respect the same as that which was suffered by the public generally, namely, a loss of stocks available to be fished, but because they were licensed to sell their catches and had established commercial enterprises based on their access to the fishing grounds they did in my judgment suffer special loss as a result of the damage to the shellfish stocks which would enable them to pursue a claim in public nuisance. 

71.(x) Hampshire Wildlife Trust Hampshire Wildlife Trust owns and occupies the Eling and Redbridge Marshes at the head of the estuary which it maintains as a nature reserve. As a result of the dredging the mudflats forming part of these reserves were covered by silt to a depth of 10-15 cm. The Trust was concerned that the silt would have an adverse effect on important feeding grounds for waterfowl. It therefore commissioned an investigation into the effects of the siltation at a cost of £100,765.83 which led to the conclusion that no long-term damage had been sustained. 

72. The Trust had a sufficient interest in the land in question to support a claim in negligence or nuisance, but did it suffer any damage over and above the mere infringement of its rights as owner and occupier? Mr. Schaff submitted that the deposit of silt of itself made it necessary for the Trust to investigate the implications for the marshes as a nature reserve and that the cost incurred in carrying out that investigation could properly be regarded as damage flowing from Jan de Nul’s wrongful act. Mr. Hamblen, on the other hand, submitted that in a case of this kind an occupier of property is only entitled to recover for actual damage to the property and cannot recover in negligence or nuisance the cost of finding out that no damage has in fact been suffered. 

73. This argument is scarcely an attractive one if, as must usually be the case, there has been some form of physical interference with the property in question which has given rise to the need for an investigation. In the present case Jan de Nul caused silt to be deposited on land owned and occupied by the Trust. It thereby committed an actionable nuisance by interfering with the Trust’s use and enjoyment of its land, although the damages recoverable for that nuisance would reflect the nature and degree of the interference. In a case where it is necessary for the landowner to carry out investigations to determine the long term effect of an interference of that kind, I do not think that it is an answer to his claim to say that no damage has been done. Nor can the cost incurred in carrying out an investigation be classed as pure economic loss; rather it is a case of loss incurred in response to and by reason of a physical interference with property. If the investigation was a reasonable response to the interference with his property the owner can in my view recover the costs incurred in carrying it out. It may well be that he will be bound to give credit against his claim for any positive benefit which has flowed from the defendant’s act, but I can see no grounds for saying that he is unable to recover any part of the expense which he has been forced to incur merely because the interference with his property has been shown to have had no harmful consequences. 

 Liability of Jan de Nul to ABP 

74. As I have already mentioned, ABP initially carried out some remedial work in the affected areas using its own dredgers. It also incurred expenses in surveying and sampling the areas of siltation and paid for the cost of the investigation into the effects of the deposits on Eling and Redbridge marshes. The costs incurred by ABP amounted in all to £778,515.47 which it sought to recover by withholding from Jan de Nul money due under the dredging contract. That led to a dispute and eventual proceedings between Jan de Nul and ABP and finally to the assignment by ABP in May 1999 to Jan de Nul of its rights as a co-insured under the policy. In the present proceedings Jan de Nul seeks to recover that sum from Royale Belge on the grounds it incurred a liability in that amount to ABP which it is entitled to recover under the policy, or on the grounds that it represents the amount which ABP was entitled to recover as an insured and which it can therefore recover as assignee of ABP’s rights under the policy. 

75. It is convenient to deal first with the question of Jan de Nul’s liability to ABP. As I have already said, ABP is charged under the Transport Act 1981 with the duty of operating and maintaining the port of Southampton. Mr. Schaff submitted that as conservator of the port ABP is entitled at common law to recover the cost of removing obstructions to navigation from those responsible for creating them in cases where the obstruction has been caused by negligence. In support of that proposition he drew my attention to a line of authority beginning with The Ella [1915] P. 111. In that case the defendants’ vessel had negligently collided with and sunk a barge in the port of Southampton thereby causing an obstruction to navigation. The harbour authority incurred expense in lighting and buoying the wreck which it sought to recover from the defendants. The court held that the plaintiff was under a duty both by statute and at common law to keep the channel fit for navigation and that the defendants were in breach of duty towards the plaintiff which was entitled to recover the expenses it had incurred in performing its duty to abate the nuisance. 

76. The decision in The Ella was approved and applied in Dee Conservancy Board v McConnell [1928] 2 K.B. 159. In that case a vessel sank through the negligence of her owners in the River Dee obstructing navigation. The plaintiffs as conservators of the river Dee sought to recover from the defendants the costs which they incurred in removing the obstruction. The Court of Appeal held that they were entitled to do so at common law. Scrutton L.J. considered (at page 167) that the Board had a common law right to remove the obstruction and recover the cost from the defendants by virtue of the fact that it had a duty to maintain the navigable channel. I do not understand his conclusion to rest on his earlier reference to the fact that the Board was also the owner of the river bed. Nor did any such consideration play a part in the reasoning of either Sankey L.J. or Russell L.J. 

77. These two authorities were considered in The Putbus [1969] P. 136 in which the Court of Appeal was concerned with the nature of the liability incurred towards the harbour authorities of Rotterdam by the owners of a vessel which caused a collision and consequent obstruction of the navigable channel. Lord Denning M.R. said at page 150F: 

 "That is a liability of a type which is imposed by the common law of England, namely a liability to damages for negligence. By our English law there is a public right of passage through our navigable channels, whether in a port or the approaches to it. That right is infringed when, through negligence on the part of the owners, a vessel has sunk in such a position as to cause obstruction in the channel. The public authority concerned - the Port Authority, or the Crown, as the case may be - is in duty bound to remove the obstruction, and, having done so, it has a common law right to recover against the owners as damages, the reasonable cost of the work: see The Ella [1915] P. 111; and Dee Conservancy Board v McConnell [1928] 2 K.B. 159." 

 Similar statements of principle are to be found in the judgments of Edmund Davies and Phillimore L.J.J. 

78. These authorities do in my view support Mr. Schaff’s submission that where an obstruction to navigation has been caused by negligence it is the duty of the port authority to preserve rights of navigation which provides the foundation for the right to recover the cost of removing that obstruction from the person who has caused it. There is no reason in principle to restrict this right of recovery to cases of obstruction by wreck; on the contrary, I think that it must be co-extensive with the harbour authority’s duty to remove obstructions to navigation whatever their nature may be. I am satisfied, therefore, that Mr. Schaff is right in saying that ABP was entitled at common law to recover from Jan de Nul the reasonable cost of removing siltation from those areas in which it represented an obstruction to navigation. 

79. Two items of expenditure incurred by ABP cannot readily be brought within this principle: the payment to the Waterside Fisherman’s Association and the cost of investigating the effects of siltation on the Eling and Redbridge Marshes. However, insofar as ABP itself incurred liability to those claimants it did not do so alone: Jan de Nul also incurred liability to them and therefore ABP became entitled to claim a contribution from Jan de Nul under the Civil Liability (Contribution) Act 1978. In the circumstances of this case responsibility for the siltation as between ABP and Jan de Nul rests squarely with Jan de Nul as the contractor. It is likely, therefore, that if contribution proceedings had been commenced ABP would have recovered a full indemnity. However, insofar as ABP recovered less than a full indemnity it would be entitled to claim under the policy and the benefit of any such claim would be capable of passing to Jan de Nul under the assignment. 

80. Apart from the contract, therefore, the circumstances in the present case were such as to entitle ABP to recover from Jan de Nul the costs which it incurred in dealing with the siltation of the estuary and its consequences. But of course, as Mr. Hamblen pointed out, the relationship between Jan de Nul and ABP was in fact governed by the terms of the dredging contract which incorporates the Conditions of Contract of the Institution of Civil Engineers (6th edition) ("the I.C.E. Conditions"). Clause 22 of the I.C.E. Conditions, he submitted, contains a carefully constructed code under which the risk of loss or damage arising out of the execution of the works is to be borne by the contractor. Accordingly it leaves no room for any kind of extra-contractual liability on the part of Jan de Nul which could be the subject of a claim under the policy. 

81. While I can see the force in Mr. Hamblen’s argument that in principle liability on the part of Jan de Nul to ABP in respect of damage arising out of the execution of the works sounds in contract rather than tort, I do not think that it carries Royale Belge very far in the present case because clause 7 of the Brokers’ Clauses provides in terms that contractual liability is covered if it results from an event which would itself give rise to liability in tort. The question remains, therefore, whether negligent acts or omissions which resulted in the deposit of silt in various parts of the estuary were such as would render Jan de Nul liable to ABP in tort at common law and for the reasons I have given I am satisfied that it did. 

 Liability of ABP to third parties 

82. Insofar as Jan de Nul seeks to recover as assignee of the rights of ABP under the policy it is necessary to deal briefly with the question of ABP’s liability to third parties. I need say little about this, however, since it was accepted on behalf of Royale Belge that on the issue of negligence ABP’s position was the same as that of Jan de Nul. Moreover, Mr. Hamblen did not suggest that questions of causation might require a distinction to be drawn between the positions of ABP and Jan de Nul and accordingly it must follow that ABP incurred liability to the third party claimants on the same grounds and to the same extent as Jan de Nul. 

 The assignment 

83. Before turning to consider the issues which arise in relation to the terms of the policy it is convenient to consider the position in relation to the assignment between ABP and Jan de Nul. ABP sought to recover the costs which it incurred in dealing with the siltation by withholding money due to Jan de Nul under the dredging contract. Jan de Nul disputed its right to do so and that led to proceedings between them which provide the background to the assignment. The assignment itself which is dated 28th May 1999 records in the preamble that the parties wish to enable Jan de Nul to recover all the expenses incurred in dealing with the siltation damage without finally compromising liability for those expenses as between each other until the claim on the policy has been resolved. On that basis ABP assigned absolutely to Jan de Nul its rights under the policy to recover in respect of all or any part of the expenses. 

84. It was not disputed that this assignment was effective to transfer to Jan de Nul any rights which ABP then had as an insured under the policy to recover the expenses which it had incurred in seeking to deal with the siltation problem. However, Mr. Hamblen submitted that the assignment was of no practical effect, because ABP ceased to have any right to recover under the policy when it recovered its loss from Jan de Nul by withholding money otherwise due under the dredging contract. 

85. The present action was begun by writ issued in December 1998; points of claim were served later that month. Jan de Nul’s primary case as pleaded in paragraph 7 of its points of claim is that it incurred "non-contractual" liability to ABP by interfering with areas of the river bed owned or occupied by ABP or by causing ABP to incur liability to third parties in tort. It is alleged that ABP acted reasonably in incurring the costs of remedial measures and that it was entitled to recover those costs from Jan de Nul in negligence or nuisance or under the 1978 Act. It is then alleged that ABP has validly set off the amount of its claim against sums otherwise payable to Jan de Nul under the dredging contract and on that basis the expenses are said to be recoverable by Jan de Nul under the policy as representing the loss referable to its liability to ABP. The assignment was not made until the following May and it was not until July 1999 that an alternative case was introduced in paragraph 8(A) of the points of claim under which Jan de Nul claimed as assignee of ABP’s rights under the policy. 

86. It is quite clear that ABP did purport to set off its claim against money due under the dredging contract. In September 1997 it purported to withhold £641,617.01, but that exceeded the amount then due to Jan de Nul and the net amount withheld was in fact only £304,082.28. However, subsequent interim accounts included a deduction for the full amount of ABP’s expenses and payment was made only for the balance. Whether ABP was strictly entitled to withhold money in this way, either under clause 49(1) of the I.C.E. Conditions or the general rules of law, is in my view of little importance given that Jan de Nul had, as I have held, incurred liability to ABP and that its primary case is that the set-off was valid and effective. The thrust of Mr. Hamblen’s argument was that on this view of the matter the effect of the set-off was to compensate ABP in full thereby leaving it with no claim capable of being pursued under the policy. In my judgment that must be right. Mr. Schaff sought to persuade me that the assignment was not intended to enure to the benefit of Royale Belge and I accept that that is so, but that is nothing to the point if ABP no longer had anything of value to assign. It is clear that when ABP withheld money due under the contract it did so in order to recoup its losses and in those circumstances I can see no basis for saying that it retained any right to recover under the policy in respect of them. It follows that in my judgment Jan de Nul’s right to recover must depend on the existence of its own liability to third parties, including ABP, rather than on any right to recover under the policy that may once have been vested in ABP. 

 The Policy 

87. It follows from what I have said thus far that in my judgment Jan de Nul is able to bring itself within the opening paragraph of section 1.1.1 of the General Conditions and the corresponding provisions of the Brokers’ Clauses. Mr. Hamblen submitted, however, that the nature of the liabilities and the circumstances in which they were incurred were such that they fall outside the scope of the cover afforded by the policy. In order to consider this submission it is necessary to examine the terms of the policy in more detail. 

 The policy terms 

88. The policy includes the following terms: 

    GENERAL CONDITIONS 

     . . . . . . . . . . . . . . . . . . . . 

 Section 2 - SPECIAL COVERS 

 2.1 Risks of fire, flames, explosion, smoke, water, pollution, environmental impairment and nuisance to neighbours 

    . . . . . . . . . . . . . . . . . . . . 

 2.1.3 NUISANCE TO NEIGHBOURS 

 The cover includes personal and property damage for which compensation can be claimed on the basis of section 544 of the Belgian civil code regarding nuisance to neighbours or on the basis of similar provisions of foreign law. 

    . . . . . . . . . . . . . . . . . . . . 

 Yet the cover will not include non-consequential immaterial damage for the risks of environmental impairment and nuisance to neighbours. 

     . . . . . . . . . . . . . . . . . . . . 

 Section 6 - EXCLUSIONS 

 The insurance cover is not granted for the following cases: 

     . . . . . . . . . . . . . . . . . . . . 

 6.6 Damage resulting from non-performance or partial performance of contractual undertakings, such as late execution of an order or a work, costs made for recommencing or correcting the work that was wrongly executed. 

    . . . . . . . . . . . . . . . . . . . . 

     BROKERS’ CLAUSES 

     (in their amended form) 

 10. Explanation of risk 

 The guarantee of this policy is general and extends to all cases in which claims can be made against the third party liability of the insured. The clarification below is purely illustrative and shall not be interpreted in a limited manner. The guarantee concerns, inter alia, 

 10.8 Neighbour nuisance on the basis of Article 544 of the Civil Code or similar foreign legislation. Neighbour nuisance caused by an environmental pollution is only covered if the provisions of Article 11.3 are met. 

 11. Exclusions 

 The only exclusions are: 

     . . . . . . . . . . . . . . . . . . . . 

 11.9 - Gross negligence 

 Gross negligence is defined as the loss in respect of which the insurer indicates that it is the result of working procedures knowingly imposed by the management as specified in art. 7, which are unacceptable according to the advice of a qualified person under the circumstances, having regard to financial, technical and other possibilities. 

    SPECIAL CONDITIONS 

 BROKERS’ CLAUSES 

 The brokers’ clauses "Liability insurance" issued by Messrs. J. VAN BREDA & Co shall apply with the following changes: 

     . . . . . . . . . . . . . . . . . . . . 

 3) Art. 11.9 - Foreseeable damage is replaced by the following text: 

 Art. 11.9 - Serious fault 

 Serious fault is defined as : the damage with respect to which the insurer shows that it results from working methods knowingly* imposed by the management, as is meant by article 7, and which, in the opinion of an impartial person who is familiar with the matter, are regarded as unacceptable in the given circumstances, taking into account the economical, technical and other possibilities. 

 *Note: It was agreed that the word ‘deliberately’ in the text of the Special Conditions should be read as ‘knowingly’. 

 EXCLUSIONS 

 Only the following [original emphasis] are excluded from cover: 

     . . . . .. . . . . . . . . . . . . . . 

 - non-accidental pollution 

     . . . . . . . . . . . . . . . . . . . . 

 - damage resulting from non-performance or partial performance of contractual undertakings, such as late execution of an order or a work, costs made for recommencing or correcting the work that was wrongly executed, professional liability" 

 Special cover - Neighbour Nuisance 

89. Although it did not come at the forefront of Mr. Hamblen’s submissions, it is convenient to deal at this point with the effect of section 2 of the General Conditions and the corresponding provisions in the Brokers’ Clauses which deal with liability for neighbour nuisance under Article 544 of the Belgian Civil Code and similar provisions of foreign law. 

90. Section 2 of the General Conditions contains what are described in the heading as ‘Special Covers’. The first three sub-sections deal with liability arising from particular causes or in particular circumstances; the fourth contains certain limitations on the cover provided in these cases. Mr. Schaff submitted that the liability which Jan de Nul incurred to the third party claimants in the present case was covered by section 2.1.1 because it arose under rules of common law which are similar to those based on Article 544 of the Belgian Civil Code. Mr. Hamblen took issue with that on two main grounds. He submitted that each of the first three sub-clauses of section 2 contains a complete code dealing with the particular type of damage to which it refers and that accordingly liability for nuisance to neighbours is only covered to the extent that it falls within the provisions of section 2.1.3 and is then subject to the limitations imposed by section 2.1.4. Under Belgian law a contractor in the position of Jan de Nul could not incur a liability on this basis to the owner or occupier of adjacent property and therefore even if liability under Article 544 is broadly analogous to liability in nuisance at common law, such liability is not covered by the policy. Secondly he submitted that liability for public nuisance in English law is fundamentally different in nature from the liability which arises as between neighbours under Article 544 and therefore falls outside the cover against liability for nuisance altogether. 

91. Having regard to the way in which the General Conditions are constructed, I think there is some force in the argument that Section 2 is intended to set out in full the terms on which cover is granted against liability arising from the particular causes of loss to which it refers. However, clause 10 of the Brokers’ Clauses, which in general take precedence over the General Conditions, provides an explanation of the risk in terms which make it quite clear that cover extends to all cases of third party liability and that the examples which then follow are simply illustrative. These include in clause 10.8 liability in nuisance under Article 544 of the Civil Code or similar provisions of foreign law. Subject to the terms of clause 10.8 itself, therefore, I do not think that the policy as a whole can be read in quite such a restrictive way as was suggested by Mr. Hamblen. However, clause 10.8 of the Brokers’ Clauses itself contains restrictions on the scope of cover against liability for neighbour nuisance and when one reads the policy as a whole I think that there can be little doubt that these were intended to apply to claims in respect of a liability of this kind. Jan de Nul does not need to bring itself within the scope of clause 2.1.3 of the General Conditions as such, since, as clause 10 of the Brokers’ Clauses emphasises, the policy is intended to cover third-party liability of every kind. However, if liability does fall within clause 10.8, cover must be understood to be subject to the limitations set out in that clause. In the present case, however, the limits of cover as stated in the Special Conditions render this academic, subject only to the question of pollution.. 

92. The debate over whether any of the third party claims fell within this part of the cover centred on whether a contractor carrying out works on land occupied by his employer could be liable for neighbour nuisance under Article 544 of the Belgian Civil Code and whether liability in English law for private nuisance or public nuisance was a liability on the basis of "similar provisions" of English law. Two expert witnesses, Professor Dr. Hugo Vandenberghe of the University of Leuven and Mr. Gérald Straatman, a practising lawyer and partner in the firm of Roosendaal Keyzer, Antwerp, gave evidence of the position under Belgian Law. It is apparent from their evidence the position of a contractor in relation to liability for neighbour nuisance is the subject of hot debate among commentators and practising lawyers alike. It was common ground that since 1960 the Belgian Supreme Court has developed a law of nuisance based on Article 544 of the Civil Code (which deals with the incidents of ownership) to regulate the interference by neighbouring occupiers of property with the use and enjoyment of each other’s land. The law rests on the principle that where there is an established equilibrium between neighbouring estates, one who disturbs that equilibrium by unreasonable interference with his neighbour’s use and enjoyment of his property must pay compensation as a means of restoring the equilibrium. This principle has been developed by the Supreme Court in a series of decisions, but in none of these has it yet been finally decided whether a contractor carrying out work on one property can have a sufficient presence on the land to incur personal liability on this basis. Prof. Vandenberghe was of the opinion that a contractor who is carrying out work of a kind which involves a sufficient exercise of the attributes of ownership can incur such a liability and he thought that when the issue does eventually arise for consideration the Supreme Court is likely so to decide. Mr. Straatman, on the other hand, doubted whether the Court would go that far and he was able to point to a number of decisions of the lower courts rejecting that proposition. However, there is no doctrine of stare decisis in Belgian law and the matter is currently free from authority at the highest level. Both witnesses were able to point to opinions of learned commentators tending to support their particular opinions. 

93. Tempting as it is to embark on a detailed analysis of the problem with a view to deciding where Belgian law currently stands on this question, I do not think that it is necessary or appropriate to lengthen this judgment by doing so. Ultimately all I need to decide is whether liability in nuisance or public nuisance under English law is "similar" to the liability which arises under Article 544 of the Belgian Civil Code. I therefore propose to summarise my conclusions on the current state of Belgian law as briefly as I can. 

94. There have for some time been a number of commentators who hold that in principle it is possible for a contractor to incur liability under Article 544 if he exercises to sufficient degree the attributes of ownership of the property from which the nuisance emanates. One can detect in the writings a certain movement in that direction over the years, but I think it is fair to say that the main weight of opinion remains the other way. Moreover, there have been a number of decisions in the lower courts consistently rejecting the view that a contractor can be held liable under Article 544. Prof. Vandenberghe placed some reliance on two fairly recent decisions of the Supreme Court, one a decision of 7th December 1992 and one a decision of 17th November 1995, but neither of these directly concerned the position of a contractor and I prefer the view of Mr. Straatman that neither of them affords much guidance on the present issue. However, the outcome of any given case may depend to some extent on the nature and duration of the operations which the contractor is carrying out and on the extent to which he is in control of the land from which the nuisance emanates. The Supreme Court has developed the principles of neighbour nuisance to meet a certain need and may well develop them further in a way which is consistent with the underlying principles. If the test to be applied is whether at the time in question the defendant was exercising the attributes of ownership over the land from which the nuisance emanated, the question then essentially becomes one of fact and degree and if the issue arose in a case involving a contractor who had a high degree of practical, if not legal, control over the land, I can see the possibility that the Supreme Court might develop the law in such a way as to hold him liable. However, in a case such as the present I think it unlikely that the contractor would be held to have had such a degree of control over the land on which the works were being carried out that he would be considered to be exercising sufficient attributes of ownership. I therefore think it unlikely that Jan de Nul would be held to have incurred liability to any of the neighbouring property owners under Article 544 if the events in question had taken place in Belgium. 

95. This brings me to the question whether liability for private or public nuisance is a liability under provisions of English law "similar" to those of Article 544 of the Belgian Civil Code. The concept of neighbour nuisance in Belgian law is based on the principle that the owner of property must not make use of it in a way which unreasonably interferes with the enjoyment of neighbouring property. The policy in the present case is a commercial contract designed to protect the insured against third party liability and was entered into in contemplation of work being carried out outside Belgium, in this case in England. In this context one would expect it to cover liability for interference with the use or enjoyment of neighbouring property regardless of the precise jurisprudential nature of the liability and I think the word "similar" must be construed with that in mind. If the insured has incurred liability under English law as a result of activities on land which have given rise to an unreasonable interference with the use and enjoyment of neighbouring land, that in my view is sufficient for liability to have arisen under provisions of English law which are "similar" to Article 544, even though under Belgian law the insured would not have been held liable in the same circumstances. If it had been intended to restrict cover for this kind of liability to cases in which liability would have arisen under Belgian law, more explicit language could easily have been used. Moreover, it would have been necessary to qualify clause 10 of the Brokers’ Clauses to make it clear that the cover against this kind of liability was restricted in that way. In my judgment, therefore, liability for private nuisance does fall within the scope of the cover. 

96. Liability in public nuisance, however, raises more difficult questions. Although it does sometimes arise for consideration in the context of an interference with the plaintiff’s use and enjoyment of land similar to that which would support a claim in private nuisance (see, for example, Attorney-General v P.Y.A. Quarries Ltd [1957] Q.B. 169), that is not its essential nature. Perhaps it is most commonly encountered in the context of obstruction of the highway or of a navigable waterway interfering with the public right of passage, but, as the editors of Clerk & Lindsell point out in paragraph 18-05, the scope of public nuisance is wide and the acts and omissions to which it applies are all unlawful. Private nuisance, on the other hand, is only concerned with interference with the use and enjoyment of land and may be committed by doing acts which are not necessarily unlawful in themselves. The question which arises in the present case is whether liability for public nuisance by reason of the interference with the public right of navigation is liability on a basis similar to that of neighbour nuisance under Article 544. I do not think it is. In my view there is a significant distinction between liability for interference with the use and enjoyment of neighbouring land and liability for interference with the enjoyment of public rights. In my judgment, therefore, liability in public nuisance does not fall within this limb of cover, but that does not prevent it from falling within the broad cover contained in Section 1 of the General Conditions and clause 10 of the Brokers’ Clauses. 

 Exclusions from cover - clause 6.6 

97. Mr. Hamblen’s primary submission on the effect of the policy terms, basing himself on clause 6.6 of the General Conditions and the corresponding exclusion in the Special Conditions, was that any costs incurred in carrying out work which properly fell within the scope of the dredging contract itself were excluded from the cover. He submitted that it made good sense to exclude them because all the work which is to be carried out under the contract is paid for in the contract price and if Jan de Nul were permitted to recover such costs from its insurers as well it would in effect be paid twice for work it had contracted to do. At first sight this is an attractive argument, but it is necessary to bear in mind two things: first, that this is a policy of insurance against liability to third parties and must be construed with its basic purpose in mind; secondly, that circumstances may arise in which under a contract of this kind a contractor may be required to carry out additional work at his own expense for which he receives no additional remuneration. In one sense, of course, it can be said that he receives payment for such work as part of the agreed price, but in reality the contract may simply impose on him the risk of certain events. In such a case he may or may not be insured against the effects of their occurrence. 

98. Both the General Conditions and the Special Conditions exclude damage arising from non-performance or partial performance of contractual undertakings, though not quite in identical terms since the General Conditions make no mention of professional liability. However, since the Special Conditions take precedence over the General Conditions they must be regarded as governing the parties’ relationship. The clause in the Special Conditions excluding liability for damage resulting from the non-performance of contractual undertakings is not altogether easy to construe. Mr. Hamblen quite properly submitted that it should not be construed with hindsight as if damage by siltation were the only or even the primary risk which the parties had in mind and I agree that there are many ways in which a contractor in Jan de Nul’s position might be expected to incur liability to third parties, although it is fair to say that the evidence of the experts suggests that in the case of dredging contractors siltation of surrounding areas is one well-recognised ground of liability. The fact remains, however, that taken on its own the expression "damage resulting from non-performance or partial performance of contractual undertakings" is capable of being given a very wide construction and I agree with Mr. Schaff that if the clause were to be construed as extending to the consequences of any breach of the dredging contract it would rob the insured of much of the protection which he was entitled to expect from the policy. One cannot ignore the fact that this is a policy which is expressed to cover Jan de Nul against liability arising under a wide variety of circumstances, as the section of the Special Conditions headed ‘Provisions’ makes clear, and in which ABP is itself treated as a third party for the purposes of the insurance. It must also be borne in mind that the insurer was aware of the terms of the dredging contract when the policy was issued. 

99. I think that some indication of the intended scope of this exclusion can be gleaned from the references to the late execution of work and the costs of correcting work incorrectly carried out. These suggest that the parties intended to exclude liability arising between Jan de Nul as contractor and ABP as employer. Another pointer in the same direction is the addition in the Special Conditions of the reference to "professional liability". It is difficult to see how liability falling within those words could arise otherwise than between Jan de Nul and ABP. It is also necessary to bear in mind that the clause is found in a policy in which ABP is treated as a third party in relation to Jan de Nul and in which cover is provided against contractual liabilities in cases where liability would also arise in tort. These lead me to the conclusion that this clause was really intended to make it clear that cover did not extend to any liability which Jan de Nul might incur to ABP as a result of a failure to carry out, in whole or in part, the contract works or as a result of a failure to exercise due skill and care in providing professional services in connection with the works. This in my view accords with the natural meaning of the words used and is consistent with the general aims and objectives of the contract as a whole, but insofar as the language admits of more than one interpretation, I think it would be right, given the fact that it is avowedly an exclusion clause, to interpret it narrowly rather than broadly. For these reasons I am unable to accept that this clause is apt to exclude liability which Jan de Nul may have incurred to third parties as a result of a failure to perform the contract work properly, even if, as between Jan de Nul and ABP that might in other circumstances be characterised as the non-performance or partial performance of a contractual undertaking. 

100. It follows that even if Mr. Hamblen were right in his submission that Jan de Nul’s liability to the third parties arose out of its failure to perform its obligation to remove all the dredged material to the Nab Disposal Ground, that would not result in its being excluded from cover insofar as liability was incurred towards parties other than ABP. Nor do I think this result surprising. The removal of silt from areas of the estuary outside the dredged channel was not something which the contract contemplated and was in the nature of additional work. The mere fact (if it be the case) that Jan de Nul had a contractual obligation to ABP to carry out that work for no additional remuneration does not seem to me to make it surprising or unreasonable for Jan de Nul to be insured against the cost of doing so. The fact that the insurance was obtained by way of cover against liability to third parties may simply reflect the fact that in practice the work is unlikely to have been required unless the siltation had an adverse effect on third parties. 

101. Quite apart from that, however, it was essential to the success of this argument for Mr. Hamblen to establish that Jan de Nul was responsible under the contract for removing the silt which had been deposited outside the dredged channel for which it obtained reimbursement through the contract price. The dredging contract identified the location of the works as follows: 

 "The works shall be executed at the Port of Southampton in the Main Shipping Channel between the Esso terminal at Fawley and the Bury Swinging Ground at Prince Charles Container Port." 

 It then described the works in terms which included the disposal at the Nab Spoil Ground of all material unsuitable for re-use and all material surplus to requirements. The contract also provided for the maintenance of advertised depths on all ABP’s berths along the river Test between berth 207 to the west and berth 37 to the east for the duration of the contract, the maintenance of the advertised depth in the main channel throughout the contract period and  "all other works incidental to the foregoing and all other works described or implied in the Contract Documents necessary for the execution of the works." It was also an express term of the contract that Jan de Nul should ensure that all activities were carried out with minimum disruption to adjacent property and persons. There were specific provisions in the contract requiring Jan de Nul to dispose of dredged material in accordance with the licence issued by the Ministry of Agriculture Fisheries and Food. One of the terms of the licence was that any material inadvertently deposited or lost overboard should be removed as expeditiously as possible. The contract also included a specific term (paragraph 903.10) requiring Jan de Nul to exercise every care to avoid damage to adjoining structures, ground and services in the area of the works and to accept responsibility for making good any such damage at its own cost. 

102. The contract incorporated the I.C.E. Conditions of Contract (6th ed.) with a number of amendments. Those Conditions include provisions (clause 22) requiring the contractor to indemnify the employer against all claims in respect of personal injury and damage to property arising out of the execution of the works, provisions (clause 23) requiring the contractor to insure in the joint names of the contractor and the employer against liabilities for personal injury and loss of or damage to property arising out of the execution of the contract, and provisions (clause 49) giving the engineer power to require the contractor to make good defects at its own expense, failing which the employer may carry out the work himself and deduct the cost from any sums due to the contractor. Clause 49 is closely related to clause 48 which deals with substantial completion of the contract works. 

103. Mr. Hamblen submitted that the removal of deposits of silt from areas outside the main shipping channel formed part of the contract works. In my judgment it did not, except insofar as there was a positive obligation under the contract to maintain the advertised depth of water in certain areas, as there was, for example, in the relation to the berths along the river Test. Dr. Patzold and Mr. De Keyser agreed that if overspill dredging was allowed a certain amount of siltation outside the dredged channel was inevitable, and the very fact that specific provision was made for the berths along the river Test shows that the parties had in mind the possibility that that might occur. Although the contract works included the removal of all dredged material to the dumping ground, that must be understood as relating to the manner of disposal of the material taken into the dredgers and not as an obligation relating to material which the contract permitted the contractor to discharge back into the estuary in the course of overspill dredging. That is consistent both with the wording of those parts of the contract which deal with the disposal of dredged materials (see, for example, paragraph 903 15 A) and with the terms of paragraphs 1 and 2 of the conditions in the MAFF licence dealing with deposit operations. Neither of these is apt to cover the deposit of silt as a consequence of the action of natural forces. There is in my view a significant difference between the inadvertent loss or dumping of material already taken into the dredgers or barges and the movement of suspended material of the kind which occurred in the present case. To construe the contract as imposing an obligation on Jan de Nul to remove siltation from anywhere within the estuary where it might be deposited by the natural action of the wind and tides would be to impose an obligation of a quite different kind. Indeed, in the absence of any definition of the area for which Jan de Nul was responsible, it is difficult to see where the line could sensibly be drawn between those parts of Southampton Water and the Solent which fell within the scope of its responsibility and those, if any, which did not. That is not to say that in carrying out the work Jan de Nul was immune from liability if it caused excessive amounts of silt to be deposited around the estuary, simply that its liability to ABP in respect of any damage was governed by the other terms of the contract, notably clause 22 and 23. 

104. It follows that except in relation to those berths at which Jan de Nul undertook to maintain the advertised depth of water, I am unable to accept that the removal of silt from areas outside the main shipping channel was part of the contract works or that the engineer had power under clause 49(2) to require Jan de Nul to carry out such work at its own expense. For this reason also, therefore, I would hold that the loss in this case is not excluded by the terms of the Special Conditions. 

 Clause 11.9 - ‘Serious Fault’ 

105. Mr. Hamblen submitted that the present case falls within clause 11.9 of the Brokers’ Clauses, as amended and applied by the Special Conditions, which excludes liability for ‘serious fault’. This gives rise to two separate questions: how is this clause to be read in conjunction with that part of the Special Conditions which deals specifically with exclusions from cover; and does the clause as amended apply to the facts of the present case? 

106. The original form of the Brokers’ Clauses was itself subject to what appears to have been an amendment in a standard form which, among other things, substituted a new clause 11.9 headed ‘Gross negligence’ for the original clause 11.9 headed ‘Foreseeable loss’. However, in each case the clause fell within the overall scope of Clause 11 which was introduced by the words "The only exclusions are: 

. . . . . . . . ." In the Special Conditions the Brokers’ Clauses are incorporated as a whole subject to specific amendments which, allowing for minor differences in translation, exactly mirror the standard form amendments. At a later point in the Special Conditions one finds a separate section headed "Exclusions" which opens with the words "Only the following are excluded from cover: . . . . . . . . ." (original emphasis). 

There is no exclusion of gross negligence, serious fault, or anything of a like nature. 

107. The general scheme of the contract is that the Special Conditions take precedence over the Brokers’ Clauses where there is any inconsistency between them. Mr. Hamblen submitted, however, that since the Special Conditions themselves specifically incorporate the Brokers’ Clauses, including clause 11.9 as amended, that clause is not subordinated to the section of the Special Conditions dealing with exclusions from cover and that the two must be read together. This means that clause 11.9 must be treated as an additional exclusion. This submission immediately confronts one with a tension between clause 11.9 and the first line of the section dealing with exclusions which states that only the matters referred to in the clauses which then follow are excluded from cover. It is possible that the parties had in mind the result for which Mr. Hamblen contended, but in seeking to resolve the question I think it is right to bear in mind that the Special Conditions, as one can see from their terms, were drafted for this particular policy, whereas the Brokers’ Clauses and the General Conditions are standard documents. One can well understand why those who drafted the Special Conditions should have incorporated the Brokers’ Clauses lock, stock and barrel together with the standard amendment before going on to make specific provisions for the particular policy. In that context it would make good sense to define the exclusions from cover in exhaustive terms, as indeed the opening words of the section suggests was the intention. If the intention had been to exclude liability arising from gross negligence or serious fault, I have no doubt that it would have been made the subject of a specific provision within the section dealing with exclusions rather than merely being left to the uncertainty of incorporation by the route suggested by Mr. Hamblen. I think that Mr. Schaff was right, therefore, in submitting that this section of the Special Conditions should be construed as incorporating the Brokers’ Clauses as amended but without seeking to undermine the precedence given to the Special Conditions where they conflict with the Brokers’ Clauses. I agree, therefore that the only exclusions from cover are those set out in the Exclusions section of the Special Conditions and that clause 11.9 of the Brokers’ Clauses has no application in this case. 

108. However, even if I am wrong about that, I do not think that clause 11.9 assists the insurers in this case. Mr. Hamblen did not submit that Jan de Nul’s management had acted recklessly; he submitted that the purpose of the clause was to exclude the consequences of negligence of a particularly serious kind, namely, negligence in choosing the method of working. Negligence in a matter of that kind, he submitted, is likely to be of far greater significance than any individual act of negligence in carrying out the operations and is a risk which insurers would properly wish to exclude. Accordingly he submitted that the word "knowingly" in clause 11.9 should be construed as meaning little more than "consciously". 

109. I am unable to accept that argument mainly because in my view it gives no real content to the word "knowingly" which in this clause is used to describe the state of mind of the management when deciding on a method of working. A decision about working methods can scarcely be made inadvertently and it must follow in my view when one reads the clause as a whole that it is directed to a decision to adopt a particular method of working in the knowledge that it would not be regarded as acceptable by a reasonably experienced and prudent contractor. In other words, the clause is intended to exclude liability for loss caused by recklessness on the part of the insured. This is both consistent with the language of the clause itself and perfectly understandable from a commercial point of view. However, Mr. Hamblen specifically disclaimed any suggestion of recklessness on the part of Jan de Nul’s management and in those circumstances clause 11.9 can have no application. 

 Non-consequential immaterial damage 

110. I come finally to one of the more difficult issues relating to the construction of the policy, namely, the scope of cover against liability for economic loss. Mr. Hamblen submitted that the policy in this case does not extend to damage in the form of pure economic loss, save in circumstances which do not arise in this case, and that therefore Jan de Nul’s claim must for the most part fail in any event. 

111. The scope of cover is governed by section 1.2 of the General Conditions and the definitions of "immaterial damage", "consequential immaterial damage" and "non-consequential immaterial damage". The terms of section 1.2.1 of the General Conditions indicate that the basic protection afforded by the policy is cover against liability for bodily injury and physical damage to property. However, by section 1.2.2 cover is extended to include "immaterial damage", that is, "financial damage resulting from the loss of advantages connected with the exercise of a right or with the use of an object". Examples given include loss of business, loss of profits and losses flowing from the inability to use property. These are all examples of consequential financial loss which may or may not be the direct result of physical injury or physical damage to property. However, the section draws a distinction between consequential immaterial damage and non-consequential immaterial damage. Consequential immaterial damage is defined as any financial loss resulting from bodily injury or property damage covered under the policy. Loss of this kind is covered in all cases. Non-consequential immaterial damage is defined as purely immaterial damage, that is, financial loss which does not result from bodily injury or property damage. Loss of this kind is covered only when caused by an abnormal occurrence which is unintentional and unexpected as far as the insured is concerned. Finally, section 1.2.2 provides that immaterial damage consequential upon bodily injury or damage to property which is not covered by the policy is itself excluded from cover. There is nothing in the Brokers’ Clauses or the Special Conditions which adds to or subtracts from these provisions. 

112. It is not difficult to detect in these sections the scheme of cover which the policy seeks to establish. Mr. Hamblen is clearly right in my view in saying that the fundamental protection provided by the policy is cover against liability for loss represented by bodily injury and physical damage to property. To this is added cover against liability for financial loss ("immaterial damage") flowing from bodily injury or damage to property. (The need for a connection between bodily injury or damage to property as the case may be and financial loss is underlined by the final sentence of section 1.2.2.) On the other hand, financial loss which does not flow from bodily injury or damage to property is not covered except in a very limited class of cases. I agree with Mr. Hamblen that one can see here a clear intention to draw a line between what might be described as ‘consequential’ financial loss and ‘pure’ financial or economic loss. The only question which arises is whether, as Mr. Hamblen submitted, in order to be recoverable under the policy financial loss must flow from bodily injury to the claimant himself or damage to his property, or whether, as Mr. Schaff contended, it is sufficient for it to flow from bodily injury to, or damage to the property of, another person provided that the insured is liable for such injury or damage and his liability is itself covered by the policy. 

113. Again, I think one must start from the fact that the fundamental nature of this policy is a contract to indemnify the insured against liability for bodily injury and damage to property. In the ordinary way, therefore, the policy will not respond at all unless and until the insured incurs a liability of that kind. I think that the way in which section 1.2 as a whole is drafted strongly suggests that the policy addresses the question of the scope of cover solely by reference to the position of the person to whom the insured has incurred liability. Where damage to A’s property causes him financial loss over and above the cost of repairing the damage, that is consequential financial loss and recoverable under the policy. However, where A suffers financial loss as a result of damage to the property of B in which he has no direct interest, that, from A’s perspective, is pure economic loss or, in the terms of the policy, non-consequential immaterial damage. The fact that section 1.2.2 allows the recovery of pure economic loss only in exceptional circumstances and excludes altogether liability for financial loss flowing from bodily injury and property damage not covered by the policy seems to me to add further support for the conclusion that the whole of this section looks at the matter from the point of view of A and that the policy was not intended to cover financial loss caused to A as a result of damage to the property of B. 

114. Mr. Schaff reminded me that this policy was issued specifically to cover Jan de Nul against liabilities arising out of the dredging works and submitted that one of the major risks associated with work of that kind is liability for the siltation of surrounding areas. He submitted that the construction for which Mr. Hamblen contended would deprive Jan de Nul of a substantial part of the protection which it could expect to obtain from the policy. If the language of the policy were genuinely ambiguous this argument might have some force, but I do not think it is. Of course it can be said that the definition of consequential immaterial damage does not itself identify the person who has suffered bodily injury or damage to property, but section 1.2 and the definitions have to be read fairly as a whole without deliberately seeking to place on them a construction which favours either the insured or insurer. When that is done I think the meaning of section 1.2 is clear. 

 Abnormal occurrence 

115. The policy did cover non-consequential immaterial damage provided it was caused by an abnormal occurrence which was "unintentional and unexpected for the policyholder". If necessary, Mr. Schaff submitted that the present case fell within those provisions, but Mr. Hamblen submitted that Jan de Nul should not be allowed to take this point for the first time in its closing speech since it had neither been pleaded nor been the subject of any evidence from the dredging experts. I have some sympathy with this objection. It is a point which ought to have been raised clearly at or before the beginning of the trial, preferably, though not perhaps necessarily, in the pleadings so that the defendant could deal with it in evidence if it was thought appropriate to do so. Although it is ultimately for the court to decide whether what happened in the present case was an abnormal occurrence within the meaning of the policy, the court is likely to benefit from expert evidence when it comes to making a decision on a matter of that kind. This is not the sort of point which can be raised without proper notice, but no application to amend the pleadings was made and in all the circumstances I do not think that it should be admitted in this way. Quite apart from that, however, I am far from persuaded on the evidence which is available that the damage in this case was caused by an "abnormal occurrence" within the meaning of clause 1.2.2. In the present context this phrase must be intended to refer to an unusual event, but by common consent the deposit of silt outside the area being dredged is a well-recognised risk of this kind of work against which proper precautions can and should be taken. The damage may have been abnormal in degree (although there is no clear evidence one way or the other about that), but it was not abnormal in its nature or origin. It is fair to say that by the end of the trial this point was no longer being seriously pursued. 

116. It follows that in my judgment Royale Belge is not bound to indemnify Jan de Nul against liability to third parties for losses which do not flow from bodily injury to, or from damage to the property of, the third party claimant himself. This is a matter of some potential importance if only because almost half the amount of the claim in this case relates to remedial work carried out in the area of the Marchwood Channel and Basin in order to restore the previous depth of water. It raises the question, therefore, how liability in negligence to ABP as conservator of the port is to be characterised under this policy. Perhaps the first point to make in this context is that I am here concerned with the construction of a policy of insurance, not directly with the distinction which has been drawn in the law of negligence between loss flowing from damage to property in the ownership or possession of the claimant and loss flowing from damage to property in which he has some lesser interest which is described as ‘pure economic loss’. The precise relationship between the claimant and the property damaged which is necessary for the loss to be recoverable under this policy depends on the construction of the contract as a whole. In the present case ABP’s position as conservator of the port carried with it a responsibility for the maintenance of the port and a right to recover in negligence damages in respect of the cost of removing obstructions to navigation. Bearing in mind the nature of the policy I think that it is to be construed as extending to a liability of this kind. Mr. Hamblen accepted that in cases where silt was deposited on land owned or occupied by ABP the cost of removing it (assuming that to be justified) would be recoverable as the cost of making good damage to property. In the present case I think that the nature of ABP’s responsibility for and interest in the physical condition of the waterway is such that the liability of Jan de Nul to ABP for damage represented by the cost of removing silt from the river bed in order to restore the previous depth of water is also properly to be characterised as a liability for damage to property rather than one for "non-consequential immaterial damage". This is in my view consistent with the general scheme of section 1 of the General Conditions which, as I have said, seek to exclude liability only for "pure" economic loss. It follows that Jan de Nul is entitled to recover under the policy in respect of its liability to ABP for the costs of carrying out remedial works wherever those were required. That includes the dredging of the Marchwood Channel and Basin as well as the waters in the area of Weston jetty and Marchwood wharf. 

 Non-accidental pollution 

117. Among the exclusions from cover listed in the Special Conditions is non-accidental pollution. Mr. Hamblen submitted that this excludes liability for the deposit of silt on the shellfish beds and in the area of the nature reserve at the Eling and Redbridge marshes. "Pollution" is defined in the General Conditions as 

 "impairment by alteration of the existing quality features of the air, the water [or] the earth by adding or withdrawing substances or energy" 

 and "accident" as 

 "a sudden occurrence which is unintentional and unexpected for the policyholder". 

 Clause 11.3 of the Brokers’ Clauses excludes liability for loss and nuisance caused by environmental pollution except when it arises from a sudden event which is unintentional and unforeseen. This is the context in which the simple exclusion of "non-accidental pollution" in the Special Conditions falls to be construed. 

118. I have no doubt that the expression "non-accidental pollution" takes its colour from these parts of the General Conditions and the Brokers’ Clauses. When asking what is meant by pollution, therefore, I think one must go first to the definition in the General Conditions. The first question, therefore, is whether the deposit of silt of this kind on land forming part of the estuary can properly be classed as an alteration of the existing quality features of the water or earth. That depends to a considerable extent on the nature of the land on which it was deposited and the use to which that land was previously being put. In an area which is a natural habitat and breeding ground for shellfish the deposit of a layer of silt sufficient to cause the destruction of a significant part of the stock can in my judgment properly be described as an alteration of the existing quality features of the water or earth amounting to impairment of the environment and so constitute pollution for these purposes. Where land is maintained largely in its natural state as a nature reserve I think the position is rather different, particularly if, as was the case here, the siltation has caused no significant damage. Mr. Hamblen submitted that in this case the damage cannot be regarded as "accidental" since it was not on any view the result of a sudden and unforeseen occurrence but of a particular method of working persisted in over a period of many weeks. I think that must be right and it follows, therefore, that the claim relating to the damage to the claim beds in Dibden Bay falls within the scope of this exclusion. 

 The Proces-Verbaal 

119. Through its brokers Jan de Nul notified Royale Belge in May 1997 of a possible claim under the policy and shortly afterwards Royale Belge appointed a surveyor, Mr. Sainderichin, to investigate the matter. Over the weeks that followed he was closely involved in enquiries into the cause and extent of the siltation and in discussions with Jan de Nul relating to proposed remedial measures. On 1st September 1997 Royale Belge declined liability under the policy primarily on the grounds that the claims made by the third parties were for pure economic loss. However, it indicated that it was prepared to help Jan de Nul to resist the demands which were then being made by ABP for it to carry out remedial work. In late September 1997 Royale Belge appointed Mr. De Keyser as a loss adjuster to negotiate with Jan de Nul and if possible to reach agreement on the value of the claim. At this stage some remedial work had already been carried out by ABP, but nothing had yet been done by Jan de Nul pending agreement with Royale Belge. 

120. On 6th November 1997 there was a meeting between ABP, Jan de Nul, Mr. Sainderichin and Mr. De Keyser in the course of which Jan de Nul indicated that it intended to carry out remedial work in January 1998 using its own equipment in order to limit the extent of the damage and avoid any further claims. Jan de Nul was anxious to ensure that the work was monitored by Royale Belge to avoid any argument in the future about what had been done and it was therefore agreed that someone would be present to represent the company’s interests but entirely without prejudice to the question of liability under the policy. Further discussions took place during November and December which led to a meeting between the parties at the offices of Jan de Nul’s parent company in Aalst on 5th January 1998. At that meeting Royale Belge was represented by Mr. De Keyser and Mr. Sainderichin and Jan de Nul was represented by Mr. Albert and Mr. Everaert of the parent company and by the project manager, Mr. Luypaert. The meeting culminated in the signature by Mr. Albert and Mr. De Keyser of a document headed ‘Report of Assessment’ (Proces-Verbaal van Minnelijke Schatting), generally referred to as the ‘proces-verbaal’, which records that the total amount of the damages, excluding VAT, was BEF103,171,065 (approximately £1,720,000). At the trial Royale Belge contended that the proces-verbaal contained or evidenced an agreement on the maximum amount recoverable under the policy, without prejudice to any issues bearing on questions of liability. Mr. Hamblen submitted that it therefore remained open to Royale Belge not only to dispute liability under the policy generally, but also to dispute Jan de Nul’s liability to individual third party claimants. The agreed amount as recorded in the proces-verbaal thus operated as a cap on the company’s liability, but did not represent an agreement on quantum which was subject only to policy defences of general application. 

121. Both Mr. De Keyser and Mr. Albert gave evidence about the background to the meeting, its object and the general nature of the discussions; I did not hear from Mr. Sainderichin, Mr. Everaert or Mr. Luypaert. One of the main issues for debate was the amount of silt that had to be removed. Both sides recognised that no precise figure could be calculated, but various estimates were made by reference to the size of the areas known to be affected and the depth of silt which vibrocore samples showed to be present. Mr. Albert argued for a total volume of 150,000m3, Mr. De Keyser argued for 100,000m3 and they compromised at 125,000m3. There was also a lot of detailed discussion about the costs previously incurred by ABP, about the appropriate rates for the operation of dredgers and barges, the costs of mobilisation and demobilisation and other similar expenses, the time likely to be required and the allowances which ought to be made for factors such as natural siltation and Jan de Nul’s liability under the dredging contract for removing siltation in the channel itself. In the end they agreed upon a total amount of BEF103,171,065 which is the figure to be found in the proces-verbaal. 

122. Although Mr. De Keyser and Mr. Albert both clearly understood that they had reached agreement, it seemed at one point that they might have differed in their understanding of exactly what had been agreed. In the end, however, I do not think that there was very much between them. Mr. Albert said that he understood that Royale Belge had agreed in principle to pay Jan de Nul BEF103,171,065 promptly to settle the claim outright, although he also said that he realised that the agreement reached with Mr. De Keyser would have to be approved by the company. He confirmed that if Royale Belge had paid that sum within a month or two he would have regarded the matter as closed. He firmly expected the company to make an early payment and he was not surprised, therefore, that no one from the insurers attended to monitor the work which began almost straight away. Mr. De Keyser for his part did not regard himself as having authority to bind Royale Belge to making a payment of any kind and did not understand himself to have done so. He thought he had reached agreement on a sum which would represent the full amount of liability on Jan de Nul’s claim, but without committing the company to accept liability, much less to make any payment. 

123. In the light of the background to the meeting, the uncertainty about the amount of remedial work required and the tenor of the discussions as described by both witnesses, I think that there can be little doubt that the object of these discussions was to arrive at an agreed figure for overall liability. That is consistent with the record which was made at the time of what was agreed in relation to the various elements making up the claim and also with the manner in which the figure agreed upon was recorded in the proces-verbaal itself. Mr. Albert was clearly willing to compromise in order to reach a speedy conclusion and I think that Mr. De Keyser was equally willing to accept a compromise which he could, in his own words, "defend to the insurers". Even if during the course of the negotiations there were discussions about the different factors affecting various areas of the estuary, there is nothing to suggest that the parties had made any attempt to agree separate figures for any individual areas and I am satisfied that there was in fact no attempt to agree figures otherwise than for the remedial work as a whole. 

124. When Mr. De Keyser came to record the agreement on the figure of BEF103,176,065 he used a standard document the printed text of which provided space for the insertion of the details of the loss and continued as follows (in translation): 

 "the aforementioned damages have been assessed by common agreement, insofar as it is needed to determine the value of the goods mentioned hereinafter and the possible consequent indemnity". 

 There is then space to insert a description of the damage and the amount and the printed form then continues 

 "The amount of the damages and the possible indemnity, including all and excluding none, the values were established finally and by common agreement, without any acknowledgment of liability for the damages and with reservation of all rights, covers and/or appeal and/or approval of the company involved. 

 . . . . . . . . . . . . . . . . . . . . 

 The payment relieves the company and its possible co-insurers finally and irrevocably of all obligations subsequent to [sc. in relation to?] the damages." 

 The printed text of the form appears therefore to be designed to do two things: to reserve all the company’s rights under the policy; and to provide that payment of the agreed amount releases the company from any further liability. 

125. In both these respects I think the form accurately reflects, perhaps fortuitously, the essential nature of the oral agreement reached between Mr. De Keyser and Mr. Albert. Mr. De Keyser was very conscious of his inability to bind Royale Belge and I am not persuaded that he purported to do so. Although Mr. Albert may have thought that a firm agreement had been reached and that payment was a formality, I am satisfied that he too realised that it was subject to the approval of Royale Belge. Certainly the text of the proces-verbaal itself reserves the company’s position fully and it is also of some significance that in his report to Royale Belge Mr. De Keyser described the section which recorded the details of what had been agreed at the meeting itself as "an adjustment document under the greatest reservation, with the verbal indication that further negotiations will be conducted by our representative". (I would accept Mr. Albert’s suggestion that "representative" here would be better translated "principal".) It is also necessary to bear in mind that although an agreement of this kind could well form the basis for a compromise of the entire claim, no attempt was made to quantify the damages referable to any particular area of siltation and it could therefore be of no value if Royale Belge were to dispute Jan de Nul’s liability to individual third party claimants. In my view all these considerations point in the same direction. The proces-verbaal contains or evidences an agreement between Mr. De Keyser and Mr. Albert as to the sum which Jan de Nul was willing to accept in compromise its claim under the policy and which Mr. De Keyser for his part would recommend to Royale Belge. It was intended to lead to a compromise, but there was no binding agreement between the parties unless and until Royale Belge adopted it. It never did so and accordingly Jan de Nul remains free to pursue the present claim in its full amount. 

 Quantum 

126. In the event the volume of silt removed by Jan de Nul was considerably greater than that estimated. That was largely due to the fact that although the information on which the estimates had been based was the best available at the time, it proved to be inaccurate in some significant respects, particularly in relation to the depth of siltation in some areas. However, Mr. Hamblen submitted that even if the proces-verbaal did not contain or evidence a binding agreement which placed an upper limit on the amount which Jan de Nul could recover, nonetheless the principles and the unit costs on which the agreed sum of BEF103,171,065 was based should be regarded as binding inasmuch as they reflect what were agreed to be the reasonable costs of carrying out work of the kind in question. That figure had been calculated on the assumption, inter alia, that Jan de Nul could make 9 barge trips a day at a certain daily cost. Applying that approach to the work actually carried out, and allowing for other factors such as the costs of mobilisation and demobilisation set out in the proces-verbaal, Mr. Hamblen submitted that the maximum amount which Jan de Nul could recover was BEF124,220,704, equivalent to £2,070,365 at the rate of exchange used for the purposes of those calculations. 

127. I have some difficulty accepting this submission insofar as it proceeds on the footing that the proces-verbaal is to be regarded as binding. For the reasons I have already given I am satisfied that proces-verbaal reflects the parties’ attempt to agree terms on which they could dispose of the claim under the policy as a whole. As such it reflected a willingness on the part of Jan de Nul to compromise and I can see no reason to think that either party understood or intended that if they failed to settle the claim the basis of that compromise should nonetheless be binding on them. On the other hand, I do accept that the proces-verbaal and the calculations which underlie it are of some evidential value when it comes to considering the reasonable cost of remedial work. Having said that, however, I am satisfied having heard the explanations provided by Mr. Oxford and Mr. Albert that all the costs which Jan de Nul seeks to recover in respect of its own operations were in fact incurred in carrying out remedial work and I am not persuaded that any of them were incurred unnecessarily. Indeed, apart from a suggestion that Jan de Nul had incurred unnecessary costs by over-dredging which was ultimately not pursued, Mr. Hamblen did not really suggest otherwise. I have many reservations about simply treating the figures on which the proces-verbaal was based as a reliable guide to the proper costs of the remedial work actually carried out. One is that the whole discussion was conducted in a spirit of negotiation and was therefore liable to lead to a certain amount of compromise. Another is that the whole exercise was based on estimates of the amount of silt to be removed and its distribution in different areas of the estuary. When the work was actually carried out many of the assumptions which had been made were found to be inaccurate. In these circumstances I am satisfied that Jan de Nul is entitled to recover the full amount of the expenditure which it incurred in carrying out remedial dredging works. 

 Summary 

128. In view of the complexity of this case I think it may be helpful at this point to summarise my conclusions as follows: 

(a) in the case of Marchwood military port, Slowhill Copse, Husband’s Shipyard, and Berths 30-36 Jan de Nul incurred liability to third parties in negligence and nuisance. These were all commercial berths and removal of the silt deposits was necessary to enable them to remain fully operational. Jan de Nul is entitled to recover all the costs incurred in removing silt from these areas; 

(b) In the case of Weston jetty, Marchwood Wharf, Marchwood Yacht Club, the private moorings, Marchwood Channel and Marchwood Basin Jan de Nul incurred liability to the third parties only in public nuisance. Such damage was purely financial and is excluded from cover. However, Jan de Nul also incurred liability to ABP in negligence in its capacity as a conservator of the port and this liability is to be characterised as a liability for damage to property. Jan de Nul is therefore entitled to recover the costs incurred in removing silt from these areas; 

(c) In the case of Berths 30-36 and the Itchen approaches Jan de Nul incurred liability in negligence to ABP as conservator of the port; it is therefore entitled to recover the cost of removing silt from this area; 

(d) Although Jan de Nul incurred a liability to commercial fishermen arising from the siltation of the shellfish beds, the loss represented by the compensation paid to the Waterside Fisherman’s Association is not recoverable having been caused by non-accidental pollution within the meaning of the policy; 

(e) In the case of Eling and Redbridge marshes Jan de Nul incurred liability to Hampshire Wildlife Trust in negligence and nuisance. The cost of investigating the effects of the siltation upon the marshes was recoverable by the Trust from both ABP and Jan de Nul. ABP which met the cost of the investigation in the first place was entitled to recover that cost from Jan de Nul. In this case the damage was not caused by pollution within the meaning of the policy. Jan de Nul is therefore entitled to recover the full amount under the policy. 

129. For these reasons I have reached the conclusion that the claim made by Jan de Nul succeeds in full save in respect of sums paid in settlement of the claims by the fishermen.