Neutral Citation Number: [2004] EWCA Civ 1021
Case No: A3/2003/2239
A3/2003/2248
IN THE SUPREME COURT OF JUDICATURE
COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM THE PATENTS COUNTY COURT
His Honour Judge Fysh QC
PAT 02010/PAT 02014
Royal Courts of Justice
Strand, London, WC2A 2LL

Date: 30/07/2004

Before :

LORD JUSTICE WARD
LORD JUSTICE JACOB
and
SIR MARTIN NOURSE
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Between :

	Unilin Beheer BV	Respondent/Claimant	
	- and -		
	(1)  Berry Floor NV
(2)  Information Management Consultancy Design Limited (t/a Responsive Designs)
(3)  B&Q plc	Appellants/
Defendants	

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Henry Carr QC and Hugo Cuddigan  (instructed by Wilmer Cutler Pickering Hale & Dorr)
 for the  First and Second Appellants
Philip Roberts (instructed by Willoughby & Partners)
 for the Third Appellants
Michael Tappin and Andrew Lykiardopoulos (instructed by Bristows) 
for the  Respondent

Hearing dates : 12/13/14 July 2004
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Judgment 

Lord Justice Jacob: 
1.	This is an appeal from a decision of His Honour Judge Fysh QC given on 26th September 2003.  The Judge held that Unilin’s EP(UK) No. 1 024 234 was infringed by two distinct categories of flooring product:  those manufactured and imported by the first defendant, Berry, and a product called ‘Snap-Fit’.  He held that the patent was valid.
2.	On this appeal Mr Henry Carr QC and Mr Hugo Cuddigan represent the first and second defendants (manufacturers and importers).  The third defendants are retailers who sold both kinds of allegedly infringing products.  They are separately represented by Mr Philip Roberts who sensibly and simply allied himself completely with the other defendants’ arguments.  Mr Michael Tappin and Mr Andrew Lykiardopoulos (solicitor advocate) represented the claimant patentees.
3.	The Judge resolved all issues in favour of Unilin.  Only three are raised by the defendants in this court:
i)	Construction of the key claim of the patent, claim 20.
ii)	Infringement by one of the two types of flooring in issue (not Snap-Fit).
iii)	Whether claim 20 was entitled to the claimed priority date.
It may particularly be noted that the defendants no longer challenge the judge’s finding of non-obviousness.
The Patent
4.	I begin by setting forth those paragraphs of the patent forming the basis of the debate before us.  It begins with a general statement about its field of application:
“[0001]	This invention relates to a floor covering consisting of hard floor panels.
[0002]	In first instance, the invention is intended for so-called laminated floors, but generally it can also be applied for other kinds of floor covering, consisting of hard floor panels, such as veneer parquet, prefabricated parquet, or other floor panels which can be compared to laminated floor.
5.	It then goes on to acknowledge some prior art and to point out difficulties with it:
“[0003]	It is known that such floor panels can be applied in various ways.
[0004]	According to a first possibility, the floor panels are attached at the underlying floor, either by gluing or by nailing them on.  This technique has as a disadvantage that it is rather complicated and that subsequent changes can only be made by breaking out the floor panels.
[0005]	According to a second possibility, the floor panels are installed loosely onto the underground, whereby the floor panels mutually match into each other by means of a tongue and groove coupling, whereby mostly they are glued together in the tongue and groove, too.  The floor obtained in this manner, also called a floating parquet flooring, has as an advantage that it is easy to install and that the complete floor surface can move which often is convenient in order to receive possible expansion and shrinkage phenomena.
[0006]	A disadvantage with a floor covering of the above-mentioned type, above all, if the floor panels are installed loosely onto the underground, consists in that during the expansion of the floor and its subsequent shrinkage, the floor panels themselves can drift apart, as a result of which undesired joints can be formed, for example, if the glue connection breaks.
[0007]	In order to remedy this disadvantage, techniques have already been thought of whereby connection elements made of metal are provided between the single floor panels in order to keep them together.  Such connection elements, however, are rather expensive in manufacturing them and, furthermore, their provision or the installation thereof is a time-consuming occupation.
[0008]	Examples of embodiments which apply such metal connection elements are described, among others, in the documents WO 94/26999 and WO 93/13280.
[0009]	Furthermore, couplings are known which allow to  snap floor parts into each other, a.o. from the documents WO 94/1628, WO 96/27719 and WO 96/27721.  The snapping-together effect obtained with these forms of embodiment, however, does not guarantee a 100-percent optimum counteraction against the development of gaps between the floor panels, more particularly, because in fact well-defined plays have to be provided in order to be sure that the snapping-together is possible.”
6.	Next the patent describes some general advantages of the invention and what it is by reference to claim 1 (of course unamended):
“[0012]	The invention aims at an improved floor covering of the aforementioned type, the floor panels of which can be coupled to each other in an optimum manner and/or the floor panels of which can be manufactured in a smooth manner, whereby preferably one or more of the aforementioned disadvantages are excluded.
[0013]	To this aim, the invention relates to a floor covering of the type described in the preamble of enclosed claim 1, which floor covering is further characterized in that it shows the features as described in the characterizing portion of said claim 1.
[0014]	The fact that according to the invention a snap-coupling, allowing that the panels can be shifted together, can be realized in one piece out of the MDF/HDF core, in other words out of Medium Density Fibreboard or High Density Fireboard, offers the advantage that, on the one hand, such panels can be coupled in an optimum manner and such snap-coupling offers interesting possibilities when combined with other preferred features, this in contrast to the subject matter disclosed in the prior art documents JP 6-146553, JP 6-200611, JP 6-320510, JP 7-076923, JP 7-300979, JP 7-310426 and JP 8-270193, which documents only disclose the integration of coupling means requiring an angling motion instead of a shifting motion.
[0015]	On the other hand, the floor panels of the invention still can be manufactured in a very competitive manner.
[0016]	Further, according to the invention, the floor covering described above can show a number of additional features, as described in the detailed description.  More particularly these floor coverings may show one or more of the following features:”
7.	The patent then goes on to set out no less than 49 of these “additional features.”	 Only the first matters for the purpose of the arguments:
 “ - that the coupling parts provide in an interlocking, allowing to couple the panels [sic – read this as “interlocking such that the panels are] free from play in respect to each other, according to all directions in the plane which is situated perpendicular to the aforementioned edges”
8.	After the 49 features the patent says:
“[0017]	Due to the fact that, in a preferred embodiment, the coupling parts provide for an interlocking free from play, as well as due to the fact that these coupling parts are manufactured in one piece, from the basic material of the floor panels, a perfect connection between adjacent floor panels can always be guaranteed, even with repeated expansion and shrinkage of the floor surface.”
9.	A little later:
“[0021]	The surfaces obtained with HDF and MDF also have the advantage that the floor panels mutually can fluently be shifted alongside each other in interlocked condition, even when engaged with a tensioning force.
[0022]	The inventor also found out that the aforementioned materials, in particular HDF and MDF, show ideal features in order to realize a connection, such as claimed in the claims, as these materials show the right features in respect to elastic deformation in order to, on the one hand, realize a snap-together effect, and, on the other hand, receive expansion and shrinkage forces in an elastic manner, whereby it is avoided that the floor panels come unlocked or are damaged in an irreparable manner.”
10.	And the only other passages I need specifically set out are:
“[0065]	In order to allow for a smooth assembly, in order to guarantee the necessary stability and firmness and in order to limit the quantity of material to be cut away, the difference E between the upper lip 22-42 and the lower lip 23-43, measured in the plane of the floor panel and perpendicular to the longitudinal direction of the groove 10, should preferably be kept smaller than one time the total thickness F of the floor panel 1.  For stability’s sake, normally this total thickness F shall never be less than 5 mm.”
“[0081]	An important characteristic herein consists in that the coupling parts 4-5 are provided with locking means 6 which, in engaged condition, exert a tension force upon each other, as a result of which the engaged floor portions 1 are forced towards each other.  As represented, this is realized preferably by providing the coupling parts with an elastically bendable portion, in this case the lip 43, which, in engaged condition, is at least partially bent and in this way creates a tension force which provides for that the engaged floor panels 1 are forced towards each other.  The hereby resulting bending V, as well as the tension force K resulting herefrom, are indicated in the enlargement of figure 23.”
11.	Prior to trial Unilin proposed an amendment on which nothing now turns.   But at trial Mr Tappin told the Judge that they intended to apply to amend the patent further - so as to bring the limitation of claim 20 into claim 1.  It was common ground that the dispute should be over whether the proposed amended claim is valid and infringed.    I set it out broken down into elements:
“(i)	Floor covering, consisting of hard floor panels (1) which are rectangular, i.e. elongated or square and which have a first pair as well as a second pair of opposite sides (2-3, 26-27);
(ii)	Said panels (1) at least at the edges of the second pair of opposite sides being provided with coupling parts (4-5, 28-29) substantially in the form of a tongue (9-31) and a groove (10-32);
(iii)	Whereby these coupling parts (4-5, 28-29) are provided with integrated mechanical locking means (6) comprising respective locking elements (11-13, 33-34, 46-47) extending in the longitudinal direction of the related edges;
(iv)	Which locking means (6) are made in one piece with the core (8) of the panels (1);
(v)	Whereby in the coupled condition of two such panels (1) the coupling parts (4-5, 28-29) together with said locking means (6) provide a locking in a direction perpendicular to the plane of the panels (1), as well as in a direction perpendicular to the coupled edges and parallel to the plane of the panels (1);
(vi)	Whereby the basic material of the floor panels (1), in other words, the material of the core (8), substantially consists of HDF-board or MDF-board.
(vii)	Characterised in that said coupling parts and locking means (6) being formed out of the said core (8) are realised in such a manner that two of these floor panels (1) can be engaged by shifting them laterally in a substantial planar fashion towards each other, thereby providing, substantially by means of elastic deformation of the groove, a snap-together connection in which said locking elements grip behind each other and in which the coupling parts (4-5, 28-29) and the locking means (6) are configured such that panels (1) in coupled condition at the related edges, are connected in a manner free of play.”
The italicised words add the limitation of claim 20.
12.	I set out the claim with the numbers.  These are there to improve its intelligibility.   By rule 29.7 of the Implementing Regulations, they are not to be construed as limiting the claim.
13.	The claim is much more intelligible by reference to the drawings.  I set out figures 6 and 7, which show the invention in accordance with the proposed amended claim:
Figures from the Patent in Suit EP 1 024 234

14.	It is easy to see how it works:  the tongue of one panel has a lower protrusion.    It snap fits into a recess in the lower lip of the groove.   It must be noted there that are no gaps in the joint such that the panels can move relative to each other without the joint coming undone.
15.	I must also set out claims 19 and 21:
“19.	Floor covering according to any of the preceding claims, characterized in that the panel (1) at least at one of its edges is provided with a groove (10-32) which at its lower side and upper side is bordered by lips (23-43, respectively 22-42); that the lip (23-43) bordering the lower side of the groove (10-32) extends as far as or beyond the lip (22-42) bordering the upper side of the groove (10-32), whereby the possible difference (E) between the lower lip (23-43) and the upper lip (22-42) is smaller than one time the thickness of the floor panel (1).
21.	Floor covering according to any of the preceding claims, characterized in that the total thickness (F) of each related floor panel (1) is 5 to 15 mm, and more particularly 8 mm.”
16.	Claim 19 introduces what was called the “lip length” limitation;  claim 21 the thickness limitation.
Issue 1 – Construction
17.	The only issue of construction relates to the closing words of the proposed amended claim, which are taken from original claim 20 – “free of play.”  The applicable legal principles are not in dispute – I recently set them out in paragraph 41 of my judgment in Rockwater v Technip [2004] EWCA (Civ) 381 and there is no point in repeating them here.
18.	There are three candidate constructions, Unilin’s, the defendants’ and the Judge’s.    Although he ultimately found in their favour Unilin boldly do not support the Judge’s construction.   The three candidates are:
(a)	Unilin’s construction
That “free of play” means (1) that there should be no play between panels when a floor is first laid – no gaps in the joints such that the panels are free to move and (2) that this requirement does not exclude a trivial amount of movement  that as a practical matter does not matter.   They expressed it this way:
“Sufficiently free of play to prevent gaps on the surface of the product when the panels are connected together which would be visible as such to the user at normal height.”
The bit about not being visible at normal height is what I call “a practical matter” – I prefer the latter expression but there is no difference.
(b) The Defendants’ construction
That “free of play” means there should be no gap within the joint in coupled condition which allows any horizontal movement whatsoever of that joint.
(c)  The Judge’s construction
This was: “Is the flooring sufficiently free of play to prevent gaps forming on its surface when the panels are connected together (and for a reasonable period thereafter) which would be visible to an end-user of average eyesight and being of normal height, while standing on the flooring?”
19.	The agenda behind the defendants’ construction is, that they say that it excludes much the larger by sales volume (90%) of the two classes of alleged infringement. This case is now essentially about money, given that the defendants now use an admittedly non-infringing construction.  But we were told that substantial quantities of alleged infringements have been sold.  So it could be a lot of money.
20.	Mr Tappin submitted that even if the defendants are right about construction, on the evidence the 90% infringes nonetheless.
21.	The differences between the various constructions all arise out of attempts to construe the claims in accordance with the correct principles.  The heart of the differences lies over paragraph 17 of the patent which I repeat here.
“[0017]	Due to the fact that, in a preferred embodiment, the coupling parts provide for an interlocking free from play, as well as due to the fact that these coupling parts are manufactured in one piece, from the basic material of the floor panels, a perfect connection between adjacent floor panels can always be guaranteed, even with repeated expansion and shrinkage of the floor surface.”
22.	The Judge said this paragraph would be regarded “as patentee’s (or patent agent’s) hyperbole” but nonetheless felt it was a passage which told the skilled man what the purpose of the “free of play” feature was and thus how it should be construed in the claim.  He reasoned that the feature had to achieve more than that the fit should be playless at the time of fitting – there was a promise that because of the feature, gaps would not appear over time due to expansion and contraction.  He thought that rather than guaranteeing timeless perfection, the passage would be read as promising “a perfect connection” over a reasonable period of time.   So he held that is what “free of play” meant.
23.	Both sides attacked this – essentially on the basis that it was too uncertain and cannot be what the patentee meant, either in paragraph 17 or the claim.  They asked, forensically, questions such as “How long is a “reasonable period”” and, even if you know that, “How can you tell whether there is infringement until the time is up?”     I think there is force in this – I do not think there is a temporal element in the claim.
24.	What then is one to make of paragraph 17?   Well I think it needs to be read with the knowledge of the skilled man and with regard to what would be apparent to him on reading the patent as a whole.   The evidence shows that over time lateral forces (due to contraction and expansion and the movement of heavy items on the floor) may build up.   This the skilled man would know.  He would also appreciate that if the floor is laid with no gaps in the joints (no free play), then the joint would be subject to these forces:  there could be no movement within the joint itself to accommodate contraction or expansion.   Obviously if the forces are too much the joint may start to fail.  But up until that point, it would hold, keeping a “perfect connection.”   
25.	His understanding would be confirmed by the coupling, in paragraph 17, of the “free of play feature” with “one piece” manufacture.   There are no separate bits of the joint to come undone – the forces are taken by the whole material of the panel.   That is confirmed by the closing words of paragraph 22 of the patent – saying in effect that MDF is a material which can take up expansion and shrinkage forces and so prevent unlocking or damage of the joint.   
26.	He would find further confirmation of this view from the patentee’s discussion of the prior art at paragraph 9.    This is a reference to an invention of a Mr Pervan.   He used a metal joining piece under adjoining panels to fix them together – the main drawings show the idea:

Figures from the Pervan Application WO 94/26999

27.	The picture shows a small gap, designated Δ, between the panels.   It is necessary in order to get the panel in.  It clearly provides free play in the joints between panels.  The reader of the patent in suit would surely recognise that the patentee’s emphasis on absence of free play is in contrast to this.   Mr Carr submitted that if one considered the picture as shown, the panels are in touching abutment – so there was no play in this prior art.   He submitted that the patent in suit was thus dealing with a non-problem.  I reject that argument.  True it is that as shown there is no gap between the panels.  But that supposes a perfect operative laying the floor perfectly.  The point is that the joint itself has a gap within it – a gap providing “free play”, whereas the patent in suit provides no gap – you cannot put the panels together so that there is a gap in the joint.
28.	The Judge held that Pervan taught that a play of 0.2mm was the lower limit.  Mr Carr attacked that, saying that the Judge had misread Pervan and that some lower gap was possible.   I do not think it necessary to resolve this.   Pervan clearly had, and needed, a gap.   The patent in suit does not.
29.	Rejection of the Judge’s construction does not resolve the question of whether Unilin or the defendants are right.  I do not think it unfair to state the right choice of these is as being between “free of play” meaning “free of play for practical purposes” or “absolutely free of play.”    And I think the choice, stated, that way, is clear – it means the former. 
30.	I say that because I do not think that the skilled man would regard a little bit of play which did not in practice matter as excluded by the words.  What practical reason should he have to do so?   Mr Carr invited us to reject that construction for several reasons.
31.	First he pointed out that the patent envisaged at paragraph 81 an embodiment where the panels were engaged with positive force produced by an elastically deformable construction of joint – the joint is pre-tensioned. Mr Carr called this “negative play”.  He suggested this was an indication that the patentee really meant no play whatsoever in the claim.   I just do not see how that follows.   Clearly the claim covers no play whatsoever – but it does not follow that it also does not cover so little play as to make no practical difference.
32.	More fundamentally Mr Carr objected that if the claim encompassed even a little bit of play, one could not know where its edge was.   How much play took you outside the claim?   I would reject that argument too.   It is nearly always possible, whatever the language, to set a “puzzle at the edge of the claim.” This is Sachs LJ’s happy phrase used in General Tire v Firestone Tire [1972] RPC 457.   In Milliken Denmark v Walk Off Mats [1996] FSR 292 at p.302 I said:
‘Moreover, I cannot think of any reason why the skilled man would have wanted to exclude the case of mats which leaked a very small amount.  In so holding I believe I am doing very much the same as was done by the House of Lords in, what was perhaps the first of the modern purposive construction cases, Henriksen v Tallon Ltd [1965] RPC 434.  There the claim was for a ball-point pen having a particular reservoir.  Lord Reid said at page 445:
“The claim is for a device which “prevents air from contacting the surface of the ink” and the question is what is meant by “prevents”.  The claim must be read in the light of the object of the invention …  It would be a very artificial construction of the claim to hold, that because the infringer’s plug is not very efficient though sufficient for commercial purposes, therefore there is no infringement.  That would simply be inviting infringers to take the invention but make it work inefficiently.  This plug does prevent air from contacting the ink but does not prevent all of the air from doing so.  I think that Lloyd-Jacob J was right in holding that a very substantial prevention is enough to constitute infringement.”
The same applies here.  The closure is sufficient for commercial purposes.  That the defendants’ mats let through a little water is not enough to take them outside the scope of infringement.  Mr Pumfrey says that if a little water is still within the claim, then how much water is not?  I think that it is a false question.  There are cases when the edges of a claim do contain questions of fact and degree.  For instance in Henriksen there would come a point when too much air could get in.  Likewise in Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183 there would come an angle beyond six degrees where there was no infringement.  Such a lintel might be suitable for some light loads but not suitable for heavy loads.  That it is possible to postulate difficult questions about a borderline does not make the claim so uncertain that there cannot be a reasonable degree of certainty for third parties.  Justice Holmes expressed the question of borderlines thus:
“When he has discovered that a difference is difference of degree, that distinguished extremes have between them a penumbra in which one gradually shades into the other, a tyro thinks to puzzle you by asking you where you are going to draw the line and an advocate of more experience will show the arbitrariness of the line proposed by putting cases very near it on one side or the other, Law and Science in Law Collected Legal Papers 1921, pp.232-233,”’
33.	In my judgment exactly the same sort of reasoning applies to “free of play”.    Unilin’s construction is right.
Issue 2 – infringement
34.	Mr Tappin showed us the defendants’ advertising literature and what the defendants’ witnesses said about it.  The Judge accurately summarised the position in his paragraphs 75-76:
“75.	The defendants themselves describe the products in issue as being free of gaps.  Thus:
(i)	The B&Q video of the FLOORMASTER LOC flooring refers to the connections as being ‘seamless’.
(ii)	B&Q’s brochure for March 2002 describes the same product as having planks which ‘lock together to make a firm tight join with no gaps’.
(iii)	The ‘Floormaster’ information from IMC’s website (May 2002-X19) describes the fit as being ‘tightly butted together.   There are no cracks to trap dust …’
(iv)	The ‘Carpetright’ website for May 2002 (X20) describes INTERLOC SUPREME flooring as having ‘no gaps’.
In addition, all the defendants’ products are designed to a manufacturing tolerance of 0.05mm, which according to the evidence, would not give rise to a visible gap in a floor which had been properly laid.
”76.	B&Q called its marketing director, a Mr David Roth, to give evidence in relation to the commercial success issue which I shall consider in due course.  Mr Roth was very familiar with the flooring products sold by his employers and said that FLOORMASTER LOC did not have gaps when installed and that they did not develop gaps which were visible to a standing observer:  Confidential T6/971 and 974-975.  Dr Irle’s evidence was to the same effect:  T5/709-711.”
35.	Mr Carr did not dispute any of that, merely submitting it was not enough to prove infringement on his construction.  It proved infringement on the Judge’s construction.  It does likewise on Unilin’s construction.   It follows that the Judge’s holding that all types of product complained of infringed should be upheld. 
36.	As I have said, Mr Tappin also argued that there was infringement on the Defendants’ construction.  He said the experiments conducted on his side proved that in practice there was no possibility of movement within the joint even if, as the defendants claimed, there was supposed to be a small amount of play (0.1mm) in the joint.   The Judge was not impressed with the experiments.   For myself I think there may well be substance in Mr Tappin’s point – not least because the defendants’ literature could hardly truthfully claim no play if there was in fact some.   But in the circumstances it is not necessary to go into this and I refrain from doing so.
Issue 3 – Priority
37.	It is common ground that unless the proposed amended claim, in effect claim 20, can hold the priority date of the first priority document, then it will not be valid.  This is because there was a prior publication by the patentees before the second priority application.  In practical terms if there is a loss of priority, the patentees would have to amend further, bringing into the main claim also the features of claims 19 and 21.   This would exclude the 90% of alleged infringements.
The law of priority
38.	I turn to the legislation.   The key provision is Art. 87 of the European Patent Convention (EPC).   This says:
“(1)	A person who has duly filed in or for any State party to the Paris Convention for the Protection of Industrial Property, an application for a patent or for the registration of a utility model or for a utility certificate or for an inventor’s certificate, or his successors in title, shall enjoy, for the purpose of filing a European patent application in respect of the same invention, a right of priority during a period of twelve months from the date of filing of the first application.”
39.	The UK 1977 Patents Act, seeking to implement this, does so in the unhelpful mode of “re-write” rather than “copy out.”   The provisions are to be found in s.5.  I see no point in setting them out.   They are supposed to mean the same as Art. 87 (see s.130(7).    I prefer to work from the Convention itself, as does the European Patent Office not only in its daily work but in its jurisprudence which UK Courts should endeavour to follow (see s.130(7) and what I said about this in Beloit v Valmet [1995] RPC 705 at pp.733-737 – the point was not pursued on the appeal, [1997] RPC 489).   
40.	Of course, in relation to priority, the Convention is seeking to implement an even wider international agreement, the Paris Convention of 1883 as amended.   So it too is a relevant consideration, being the very foundation of the world-wide priority system.  Art.4 so far as material reads:
“A.   Any person who has duly filed an application for a patent .. in one of the countries of the Union … shall enjoy, for the purpose of filing in other countries, a right of priority ..”
“B.  Consequently, any subsequent filing in any of the other countries of the Union before the expiration of [12 months] shall not be invalidated by reason of any acts accomplished in the interval”
“F.  No country of the Union may refuse a priority … on the ground that … an application claiming one or more priorities contains one or more elements that were not included in the application … whose priority is claimed, provided … there is unity of invention within the meaning of the law of the country.
With regard to the elements not included in the application .. whose priority is claimed, the filing of the subsequent application shall give rise to a right of priority under ordinary conditions.”
“H.  Priority may not be refused on the ground that certain elements of the invention for which priority is claimed do not appear among the claims formulated in the application in the country of origin, provided that the application documents as a whole specifically disclose such elements.”
41.	The leading case in the EPO on priority is G02/98, [2001] OJ EPO 11, [2002] EPOR 167, a decision of the Enlarged Board.   The first question referred to it (and the only one answered) was:
“1(a)	Does the requirement of the ‘same invention’ in Article 87(1) EPC mean that the extent of the right to priority derivable from a priority application for a later application is determined by, and at the same time limited to, what is at least implicitly disclosed in the priority application?”
42.	The Board’s answer was:
“The requirement for claiming priority of “the same invention”, referred to in Article 87(1) EPC, means that priority of a previous application in respect of a claim in a European patent application in accordance with Article 88 EPC is to be acknowledged only if the skilled person can derive the subject-matter of the claim directly and unambiguously, using common general knowledge, from the previous application as a whole.”
43.	Mr Carr referred to other parts of the Board’s reasoning.  I set it out here and deal with the argument based on it below.
“8.3	In order to assess whether a claim in a later European patent application is in respect of the same invention as the priority application pursuant to Article 87 (1) EPC, a distinction is made in Decision T73/88 (cf. point II.(iv) above), and in a statement by third parties pursuant to Article 11b of the Rules of Procedure of the Enlarged Board of Appeal (cf. point IV above), between technical features which are related to the function and effect of the invention and technical features which are not.  This approach is problematic because there are no suitable and clear, objective criteria for making such a distinction;  it could thus give rise to arbitrariness.  In fact, the features of a claim defining the invention in the form A+B+C do not represent a mere aggregation, but are normally inherently connected with each other.  Therefore, if the above-mentioned distinction is to be made, the answer to the question whether the claimed invention remains the same, if one of these features is modified or deleted, or if a further feature D is added, depends very much on the actual assessment of the facts and circumstances of the case by each individual deciding body.  Different deciding bodies may thus arrive at different results when assessing these facts and circumstances.  Furthermore, as pointed out in the referral of the President of the EPO (cf. point III.(v) above), it has to be borne in mind that the assessment of these different deciding bodies of whether or not certain technical features are related to the function and effect of the claimed invention may completely change in the course of proceedings.  This is the case, in particular, if new prior art is to be considered, with the possible consequence that the validity of a hitherto acknowledged right of priority could be put in jeopardy.  Such dependence would, however, be at variance with the requirement of legal certainty.”
“9.	From the analysis under point 8 above, it follows that an extensive or broad interpretation of the concept of “the same invention” referred to in Article 87(1) EPC, making a distinction between technical features which are related to the function and effect of the invention and technical features which are not, with the possible consequence that a claimed invention is considered to remain the same even though a feature is modified or deleted, or a further feature is added (cf. point 8.3 above), is inappropriate and prejudicial to a  proper exercise of priority rights.  Rather, according to that analysis, a narrow or strict interpretation of the concept of “the same invention”, equating it to the concept of “the same subject-matter” referred to in Article 87(4) EPC (cf point 2 above), is necessary to ensure a proper exercise of priority rights in full conformity, inter alia, with the principles of equal treatment of the applicant and third parties (cf. point 8.1 above) and legal certainty cf. point 8.3 above) and with the requirement of consistency with regard to the assessment of novelty and inventive step (cf. point 8.1 above).  Such an interpretation is solidly supported by the provisions of the Paris Convention (cf. point 5 above) and the provisions of the EPC (cf. point 6.8 above), and is perfectly in keeping with Opinion G03/93 (cf. point II.(vi) above).  It means that priority of a previous application in respect of a claim in a European patent application in accordance with Article 88 EPC is to be acknowledged only if the person skilled in the art can derive the subject-matter of the claim directly and unambiguously, using common general knowledge, from the previous application as a whole.”
44.	This court has acknowledged the significance of G02/98 in Pharmacia v Merck [2002] RPC 41.   Aldous LJ, with whom Sedley LJ agreed, held that the leading authority in the UK on priority, Biogen v Medeva [1997] RPC 1, HL, is consistent with it even though decided before.   Aldous LJ summed up the law pithily in the following sentence:
“What is required, as Lord Hoffmann pointed out in Biogen, is that the priority document must contain sufficient material for the priority document to constitute the enabling disclosure of [the claim concerned] (p.814).”
45.	Mr Carr submitted the following:  that mere disclosure of features in the priority document is not enough.   The invention has to be the same.   And G02/98 makes it clear that the test for this is strict.   So the omission of features required by the priority document will result in a loss of priority for any claim missing those features, since in their absence the invention is no longer the same.   There is an exception – where omitted features are inessential to the invention of the priority document.  But this exception should itself be applied narrowly.
46.	Mr Carr further submitted that although the main claim in a priority document is not decisive, it at least carries great weight in determining what the invention of the priority document is.
47.	Mr Tappin submitted that the position was simpler.  He submitted that priority can be accorded to any invention the subject-matter of which is disclosed in and enabled by the priority document.  Any claim or “consistory clause” (jargon for a repetition of the main claim in the body of the specification) in the priority document is not determinative.  The important thing to focus on is whether the priority document as a whole discloses matter (i.e. information) which effectively gives the skilled man what is in the claim whose priority is in question and that that information is enabling.
48.	I think Mr Tappin must be right.   That is what both Biogen and G02/98 are saying.    The approach is not formulaic: priority is a question about technical disclosure, explicit or implicit.   Is there enough in the priority document to give the skilled man essentially the same information as forms the subject of the claim and enables him to work the invention in accordance with that claim?
49.	Before going to the details of the priority document in this case I should deal with Mr Carr’s submission about the main claim or consistory clause of the priority document, i.e. that although not determinative it is nearly so.  That he could not get out of GO2/98 or indeed any other authority.   GO2/98 refers to “the previous application as a whole,” not the main claim nor the “main statement of invention” nor the “consistory clause”. Likewise there is nothing in Art. 87 which compels or suggests this conclusion.  And Art 4H of the Paris Convention is positively against it.   The claims (if any – there is no rule that there should be) of the priority document are not determinative.   They are just part of its disclosure.   For the purposes of priority one just looks at the disclosure as a whole.   
50.	If the rule were otherwise one of the main functions of a priority document would be lost.   Inventors and their advisors would have to start worrying not only about the technical information disclosed in the document but how it was to be claimed:  have I drafted my main claim or consistory clause broadly enough?   That is not the purpose of the system: the purpose at this point is to get the information justifying the later claim into a patent office of a Union country.  If you do that, you can have your priority, whether you express that in a proposed claim, consistory clause, statement of invention, other text or drawing or in any combination of these.   Time is of the essence because the world-wide system (except for the Americans) works on the first to file basis.  The detailed framing of a claim based on that information may then be done within the Convention year.
The Priority Document in this case
51.	A masterpiece of draftsmanship this is not.   Nonetheless, bearing in mind that it will be read by a skilled man and that there are helpful drawings, I think it is clear enough.  After a very general statement to the effect that the invention relates to floor coverings consisting of panels, it sets about acknowledging the prior art.   In particular the use of metal elements is mentioned – this would be taken to be a reference to a product made in accordance with Pervan which, on the Judge’s findings had become common general knowledge.   It says that the metal elements are expensive to manufacture and that their installation is time-consuming.  The document goes on to say that the invention aims to overcome these disadvantages.  It goes on to say:
“The invention also aims at a floor covering which does not show the aforementioned disadvantages.
The invention also aims at a floor covering which shows the advantage that no mistakes during installing, such as gaps and such, can be created
Furthermore the invention also aims at a floor covering whereby the subsequent development of gaps is excluded or at least counteracted in an optimum manner, whereby also the possibility of the penetration of dirt and humidity is minimalised (p.2).”
52.	These are all important passages.   As I have said the skilled man will read them with the drawings in mind.  Note that the drawings of the priority document include the same drawings as those in the patent which I have reproduced above.    I think he would see at once how gaps are avoided and why the subsequent development of gaps is excluded or counteracted.  You can use the properties of MDF to snap fit the joint together as shown in the pictures.
53.	The priority document goes on to say:
“To this aim, the invention relates to a floor covering, consisting of hard floor panels which, at least at the edges of two opposite sides, are provided with coupling parts, cooperating which each other, substantially in the form of a tongue and a groove, characterized in that the coupling parts are provided with integrated mechanical locking means which prevent the drifting apart of two coupled floor panels into a direction perpendicular to the related edges and parallel to the underside of the coupled floor panels;  that the coupling parts and locking means are realized in one piece with the core of the  floor panels;  that the coupling parts have such a shape that two subsequent floor panels can be engaged into each other exclusively by snapping together and/or turning whereby each subsequent floor panel can be inserted laterally into the previous;  that the coupling parts  provide in an interlocking, free from play, according to all directions in the plans which is situated perpendicular to the aforementioned edges;  that the possible difference between the upper and lower lip of the lips which border the aforementioned groove, measured in the plane of the floor panel and perpendicular to the longitudinal direction of the groove, is smaller than one time the total thickness;  that the total thickness of each related floor panel is larger than or equal to 5 mm;  and that the basic material of the floor panels, of which the aforementioned core and locking means are formed, consists of a ground product which, by means of a binding agent or by means of melting together, is composed to a single compound, and/or of a product on the basis of synthetic material and/or of a chip board with fine chips (pp.2-3).”
54.	This is the consistory clause, repeated in claim 1 of the priority document,  on which Mr Carr relies so strongly.   Note that the closing part adds the lip length and thickness limitations.   
55.	The priority document continues:
“Due to the fact that the coupling parts provide for an interlocking free from play, as well as due to the fact that these coupling parts are manufactured in one piece, from the basic material of the floor panels, a perfect connection between adjacent floor panels can always be guaranteed, even with repeated expansion and shrinkage of the floor surface (p.3).”
A few paragraphs further on it says:
“The fact that the invention is applied to floor panels the basic material of which consists of the material described above, [HDF or MDF] offers the advantage that with the processing of this material, very smooth surfaces are obtained whereby very precise couplings can be realized, which, in first instance, is important in the case of a snap-together connection and/or turning connection  free from play.  Also, very special forms of coupling parts can be manufactured in a very simple manner because the aforementioned kinds of material can be processed particularly easy (sic) (p.4).”
56.	Next it says:
“The inventor also found out that the aforementioned materials, in particular HDF and MDF, show ideal features in order to realize a connection, such as mentioned above, as these materials show the right features in respect to elastic deformation in order to, on one hand, realize a snap-together effect, and, on the other hand, receive expansion and shrinkage forces in an elastic manner, whereby it is avoided that the floor panels come unlocked or are damaged in an irreparable manner (pp.4-5).”
57.	There follow several pages not relevant to the present discussion.   The next passage of relevance is:			
“In the most preferred form of embodiment, they shall be manufactured in an elongated form, such as shown in figure 1, for example, with a length of 1 to 2 meters.  The thickness, however, can also vary, but is preferably 0.5 to 1.5 cm, and more particularly 0.8 cm.
Each floor panel 1 is, at least at the edges of two opposite sides 2-3, provided with coupling parts 4-5 which allow that two adjacent floor panels 1 can be coupled to each other.
According to the invention, the coupling parts 4-5, as represented in the figures 2 to 4, are provided with integrated mechanical locking parts 6 which prevent the drifting apart of two coupled floor panels 1 into a direction D perpendicular to the respective sides 2-3 and parallel to the underside 7 of the coupled floor panels 1;  the coupling parts 4-5 and the locking means 6 are realized in one piece with the core 8 of the floor panels 1;  the coupling parts 4-5 have such a shape that two subsequent floor panels 1 can be engaged into each other exclusively by snapping-together and/or turning, whereby each subsequent floor panel 1 can be laterally inserted into the previous;  and the coupling parts 4-5 provide in an interlocking free from play according to all directions in the plane which is situated perpendicular to the aforementioned edges (pp.7-8)”
58.	Finally I should set forth two passages on which Mr Carr relied:
“Finally is noted that, according to the invention, the lower lip 23-43, as represented in figures 5 to 7, can be realized longer than the upper lip 22-42.  This has as an advantage that the coupling parts 4-5-28-29 can be realized in an easier manner by means of a milling cutter or such.  Furthermore, this simplifies the engagement of two floor panels 1, because each subsequent floor panel 1 during installation can be placed upon the protruding lower lip 23-43, as a result of which the tongue 9-31 and the groove 10-32 automatically are positioned in front of each other (p.13.)”
“In order to allow for a smooth assembly, in order to guarantee the necessary stability and firmness and in order to limit the quantity of material to be cut away, the difference E between the upper lip 22-42 and the lower lip 23-43, measured in the plane of the floor panel and perpendicular to the longitudinal direction of the groove 10, should always be kept smaller than one time the total thickness F of the floor panel 1.  For stability’s sake, this total thickness F shall never be less than 5mm (p.14)”
59.	Mr Carr submits that although the “free of play” feature is disclosed, it is always tied to two other features, namely the lip-length limitation and the minimum thickness – those matters which ended up in claims 19 and 21.    So, he says, there can be no priority for a free-standing claim to “free of play:” only a claim having all three elements could justify priority.     The drawings, he submits, add nothing – for they all have a lip length and thickness in accordance with the requirements of the consistory clause.
60.	To support his submission Mr Carr first relies upon the consistory clause and claim 1.   There, he says, is the inventor disclosing his idea in its full width.  It goes no wider than that.   I would reject that submission for the reasons I have given in paragraphs 49-50.  It proves too much.  Moreover it is purely technical and mechanical in nature.  It does not focus on the information actually conveyed to the skilled man by the priority document.  It does not apply the G02/98/Biogen test.
61.	Mr Carr also relied on those passages of G02/98 quoted above.  He submitted that here, just as in the Board’s discussion, there were three features, A+B+C (free of play, lip length limitation, and minimum thickness).   They are disclosed in combination – hence, he says, a claim to one without the other two cannot have priority.    I would reject that submission too.   The discussion at this point in the Board’s reasoning is in danger of being considered in too abstract a way.    Helpful though it was in the Board’s reaching its ultimate conclusion, what really matters is the conclusion itself.   The fact of the matter is that when features A+B+C are disclosed, a lot must turn on what they actually are.   Some inventions consist of a combination of features –the invention consists in the very idea of putting them together.  In other cases that is simply not so – the features are independent one from the other.   Whether, given a disclosure of A+B+C, there is also a disclosure of A or B or C independently depends on substance, not a formula.  The ultimate question is simply whether the skilled man can derive the subject-matter of the claim from the priority document as a whole.
62.	Next, coming to more detail, Mr Carr placed particular reliance on the passage from p.14 which I have quoted at para. 58 above.   He says the inventor is there saying the lip-length and thickness must always be as specified in the consistory clause.   He also asks us to note that the corresponding passage of the specification of the patent in suit, para. 65 quoted above at para. 10, has moved from mandatory language to “preferably” and “normally.” This, he submits, shows a widening.    He is right about the mandatory language in the priority document.  But it is  “in order to guarantee the necessary stability and firmness and in order to limit the quantity of material to be cut away.”    These things have nothing to do with freedom from play as would be self-evident to the skilled man.    As to the change made to para 65 of the specification of the patent, it is strictly irrelevant - priority is judged by comparing the claim in question with the priority document as a whole.   The text of the specification of the patent does not come into the question of priority (save, I suppose, indirectly in a case where it is relevant to the construction of the claim).
63.	Mr Tappin submits that there is nothing in the priority document which would tell the skilled man that the free-of-play feature is in any way dependent on a lip-length limitation or the thickness of the board.  He points particularly to the passages I have identified at paras.  51, 55-57 above.   None of these relate lip-length or thickness to the free-of-play feature.   The document clearly teaches generally that MDF can be used to create a snap fit connection which is free of play.   Mr Carr sought to persuade us otherwise by a convoluted argument about the reference to smooth assembly, suggesting that it was somehow related.   I reject that as an over-meticulous lawyer’s construct:  one which would never cross the mind of the skilled man reasonably seeking to get information from the document.  He would readily see generally how to make a free-of-play joint.
64.	So I think Mr Tappin is right.   There is enough information in the priority document to satisfy the GO2/98 test.   The Judge thought so too.  He analysed the disclosure and focussed on the “free-of-play” feature.   Like him I think that is a key disclosure of the priority document – and it is entirely self-evident from the document how to achieve that irrespective of lip-length ratio or thickness.   These add other advantages (e.g. thickness for stability as a floor, or low lip length to save material) but do not help in making a free-of-play connection.
65.	Accordingly I think claim 20 and the proposed amended claim 1 are entitled to priority. So, although I vary from the Judge’s construction of the “free of play” feature, I would dismiss this appeal.  I would only add that we were told that the patent is under opposition in the EPO.  Shortly before our hearing the opposition division (perhaps influenced by Judge Fysh’s decision) upheld the proposed amended claim 20 but with the inclusion of a further “temporal” limitation essentially in accordance with his construction. I understand that both parties are appealing that decision.  None of that has played any part in this appeal.
Sir Martin Nourse: 
66.	I agree.
Lord Justice Ward:
67.	I also agree.