62 As is apparent from these passages, Bristol Myers could have been determined, and was determined, without reference to a principle as categorical as that for which the applicants contend in the present case. At one extreme, it may be accepted that a patentee who knows that certain prior art will be fatal to validity, and who delays making application to amend without a reasonable explanation, will occupy a very weak position from which to seek a favourable exercise of the court's discretion. With respect, however, I cannot accept that that is the only circumstance in which an application to amend will be refused. At the other extreme, it also seems clear that a patentee who has been professionally advised that his or her claims are valid, and has no reason to doubt that advice, will be given a sympathetic hearing upon an application to amend. However, as the final passage set out above demonstrates, the decision in Bristol Myers turned not merely on the circumstance that the patentees had received no advice adverse to the validity of the patent, but, ultimately, upon Whitford J's view that, until they were advised to amend, "there was [no] good reason why they should or ought to have thought that they should apply to amend at all". In my opinion, the critical question here is whether the putative patentee had a good reason to think it necessary to amend (and, of course, the nature and justification of his or her reaction to that reason) rather than the more narrow fact of whether that reason was provided by the existence of advice that the unamended patent was necessarily invalid.
63 In subsequent cases, Bristol Myers has not been given the categorical reading contended for by the applicants here. In Matbro v Michigan (Great Britain) Ltd [1973] RPC 823, Graham J referred to Bristol Myers and to Van der Lely, and continued ([1973] RPC at 834):
I think these cases do support what I have said above in regard to delay and detriment and also draw a clear distinction between instances where a patentee knows of prior art which he genuinely, and quite properly in the circumstances, thinks is irrelevant, and other instances where, though he learns of or has been warned of objections which are available against his patent as a result of prior art, yet he takes no steps to put his specification right by way of amendment, or still worse, knowingly persists in retaining it in the unamended and suspect form. In the latter cases delay is culpable because potential defendants and the general public are entitled to plan their activities on the assumption that the patentee, though warned, has decided not to amend. If the patentee, by his conduct, lulls the public into a false sense of security he cannot thereafter be allowed to change his mind and ask for amendment, or at any rate without adequate protection being granted to the public.
Here, it seems to me, the facts are such that the case falls into the first category where, though the patentees knew of the prior art in question for some time before they applied to amend, they never, in fact, thought, or ought to have thought, nor were they advised until shortly before the application, that amendment was prudent.
Particularly in his Lordship's words appearing towards the end of this passage, the judgment of Graham J provides more obvious support for the position taken by the respondents than for that of the applicants in the present case.
64 The authorities to which I have referred were amongst a number which Aldous J considered in Smith Kline. With reference to the first of the two paragraphs which I have extracted above from Matbro (that ending with the words "granted to the public"), his Lordship said ([1989] 1 FSR at 568):
In that passage, the judge drew attention to the fact that there is a detriment to the general public by the maintenance in an unamended form of a patent which should be amended for a substantial period of time. He also drew a distinction between two categories of delay with knowledge. In the first category is a patentee who knows of the prior art and never thought or should have thought amendment was the right course. The Bristol Myers case fell within that category. In the second category is a patentee who becomes aware of an objection to a patent and takes no steps to amend. In both categories the patentee has knowledge of the prior art which prompted the request for amendment and failed to apply to amend for a substantial period of time. The difference between the two categories is the unreasonable conduct of the patentee, referred to as culpable by the judge, in not applying to amend when he knew or should have known that he should amend. In both categories, the failure to amend earlier is contrary to the public interest, but in the second [sic] category the patentee's conduct could be excused as he acted reasonably and therefore not acted in a way which was an abuse of the patent system. Thus, in a case where a patentee who is aware of the facts and either decides not to amend or takes no action, but later changes his mind, the court will refuse to exercise its discretion in his favour unless there is a good and proper reason for his failure to seek amendment promptly.
I think it fairly clear that, in the penultimate sentence of this extract, the words "second category" ought to have been a reference to the first category.
65 Subject to that minor complication, in that extract, Aldous J identified a distinction between two classes of case, in each of which the patentee knew of the relevant prior art. The first was where he or she "never thought or should have thought amendment was the right course". The second was where he or she "becomes aware of an objection to [the] patent". The difference lay, in his Lordship's view, in the "unreasonable conduct of the patentee" in the second kind of case, "in not applying to amend when he knew or should have known that he should amend". When his Lordship referred, later in the passage, to the patentee being "aware of the facts", he had in mind, in my respectful view, a patentee who was "aware of an objection" in the second class of case. This part of his Lordship's judgment gives further content to his third principle, at least in a situation in which it is necessary to make discriminations between different putative patentees, each of whom knew of the existence of the relevant prior art.
66 It seems that the first occasion upon which this court found it convenient to refer to the Smith Kline principles was Rescare Ltd v Anaesthetic Supplies Pty Ltd (Federal Court of Australia, unreported, 4 March 1993). In that case, Gummow J seems to have interpreted a passage in the judgment of Menzies J in Sly v United Development Corp Pty Ltd (1962) 106 CLR 633, 640-1 as suggesting that the conduct of the patentee was not relevant to an application to amend before the Deputy Commissioner under the Patents Act 1903 (Cth). Gummow J said that Menzies J's words "should not be taken at face value when dealing with the later legislation " (at [16]). His Honour continued (at [17]):
Lengthy delay in seeking amendment may be fatal because in the meantime the patentee has represented to the public that he has a valid claim when he knows it cannot be supported in its present form: Smith Kline and French Laboratories Ltd v Evans Medical Ltd (1989) FSR 561 at 567, a case arising under s 31 of the 1949 British Act.
I would not read these words as proposing that lengthy delay would be fatal only where the patentee knows that the relevant claim cannot be supported in its unamended form. Rather, what his Honour intended, in my respectful view, it is to give an instance of when lengthy delay would be fatal. That instance was not intended to be exhaustive.
67 The next occasion upon which this court referred to Smith Kline was Wimmera Industrial Minerals Pty Ltd v RGC Mineral Sands Ltd [1997] FCA 1063. There is nothing in the judgment of Sundberg J in that case which provides any support for the categorical position for which the applicants contend. To the contrary, his Honour was at pains to emphasise that a decision under s 105 is a discretionary one, that the principles in Smith Kline are not inflexible rules, and that, generally, there are no absolutes in this area of the law. Much the same approach was taken by Tamberlin J in Gambro Pty Ltd v Fresenius Medical Care South East Asia Pty Ltd (1999) 48 IPR 625.
68 The case which aligns most closely with the present one on the facts is ICI Chemicals & Polymers Ltd v Lubrizol Corp [1999] FCA 1417, decided in October 1999 by Emmett J. There, objections had been taken to the corresponding claim in foreign jurisdictions, and those objections had been dealt with by processes which included amendments. Yet no amendment had been sought in Australia. Indeed, Emmett J was able to find that the patentee was most probably consciously aware that the relevant claim in the Australian patent had been anticipated by the prior art relied on in those overseas jurisdictions. His Honour said ([1999] FCA 1417 at [128]-[130]):
With the benefit of hindsight, it may well be that some criticism can be directed to the conduct of Lubrizol over the period of time covered by the events that I have summarised above. From the time when the amendment was foreshadowed in the US, or from the time when the European application was amended or from the time when the voluntary amendment was lodged in Canada, Lubrizol must be taken to have a conscious awareness of the invalidity of the Patent in so far as it included Claim 1 and its dependent Claims. Nevertheless, it took no steps to amend in Australia.
However, I am not satisfied by the evidence before me that Lubrizol has endeavoured to obtain any unfair advantage by its failure to apply earlier for any amendment to the Patent and the complete Specification. There is certainly no evidence that any entity has declined to use the relevant lubricants in combination with HCFCs by reason of the presence in the Patent of Claim 1 and its dependent Claims. More significantly, there is no evidence to suggest that Lubrizol was motivated, in its failure to seek amendment earlier, by any desire to prevent such use. In any event, I do not consider that the conduct of Lubrizol in relation to the claims relating to HCFCs is such as to disentitle it to the benefit of the invention concerning HFCs.
There was clearly delay on the part of Lubrizol. However, the delay in question has not in my opinion been such that it should be characterised as unreasonable. While, in practical terms, the amendments could have been sought earlier, there was no intention on the part of Lubrizol to gain from any delay. The tactics adopted once the proceeding for revocation had been commenced were legitimate. Accordingly, I am not satisfied that, in the exercise of the Court's discretion, I should refuse to direct the amendments sought by Lubrizol.
The approach of Emmett J in ICI Chemicals provides a deal of support for the applicants' position in the present case. There are, however, important differences, in the light of which the applicants' position should be seen as less defensible than that occupied by the patentee before his Honour.
69 The forensic setting in which ICI Chemicals arose was that the applicant, the ICI company, took the initiative by commencing a proceeding for revocation. About four months later, the patentee, Lubrizol, commenced a separate proceeding against other companies, alleging infringements of claims which included claim 1 ([1999] FCA 1417 at [71] and [84]). At the time, the patentee took the view that claim 1 was invalid, but proposed to seek an amendment ([1999] FCA 1417 at [84]). Emmett J said (at [85]):
Thus, at this stage, it is clear that, on the face of it, Lubrizol was alleging infringement of Claim 1 in the wide form in which it appears in the Specification as filed. On the other hand, it is also clear that Lubrizol was not intending to rely on Claim 1 in its wider form but was intending to amend Claim 1 by incorporation into it of the qualification contained in Claim 2. In other words, it is clear enough that Lubrizol intended only to enforce Claim 2 in the proceedings that it commenced on 15 July 1997.
About a month later again, the respondents in the infringement proceeding filed their defence and cross‑claim, alleging invalidity and seeking revocation ([1999] FCA 1417 at [88]).
70 Over the course of the next six weeks or so, the patentee considered whether it ought to apply to amend claim 1, the result of which was stated by Emmet J as follows ([1999] FCA 1417 at [95]):
Thus, a tactical decision was made by Lubrizol to defer, for the time being, any application to amend Claim 1. However, it is clear that there was no intention to persist in any allegation of infringement of Claim 1 in its broader form. The tactical decision was made in order to avoid disclosure of privileged material. That appears to me to be a legitimate justification for the conduct of Lubrizol at that stage.
The deferral referred to by his Honour continued for about another year, during which the patentee was considering the legal and tactical issues that would be thrown up by an application to amend claim 1. By October 1998, the patentee had arrived at a seemingly firm view that that claim could not be defended. In that month its solicitors wrote to the solicitors for ICI stating that it would not be submitted that the claim was valid, and proposing two alternatives, each of which would have involved the revocation of the claim ([1999] FCA 1417 at [109]).
71 The revocation proceeding and the infringement proceeding came before Emmett J in February 1999, his Honour giving judgment on 31 March 1999. The patentee conceded that it could not maintain claim 1 and its dependent claims (claims 4-9) ([1999] FCA 345 at [39]). The case proceeded by reference to the other claims, which his Honour held to be valid save with respect to fair basis. The way his Honour decided the case was to hold that, if amended to overcome the fair basis point, certain of the claims would have been infringed. It was these amendments which came before his Honour in the hearing which led to the judgment on which the applicants rely in the present case. At least by that stage, there was no suggestion that claim 1 and its dependent claims ought to be amended. They had been abandoned before the main trial in the case. The patentee's early awareness of the probable invalidity of claim 1 was, however, a discretionary basis upon which it was put to Emmett J that the amendments to the other claims should not be allowed. His Honour dealt with the point in the terms I have extracted at para 68 above.
72 The critical difference between ICI Chemicals and the present case is that, here, the applicants seek to amend the very claims as to which, it is said, they were earlier on fairly clear notice of validity problems which ought then to have been addressed. By contrast, in ICI Chemicals the amendment application did not relate to the claims which the patentee earlier knew, or ought to have known, were invalid. The delay point operated only indirectly with reference to the claims sought to be amended. The significance of this to the exercise of Emmett J's discretion is to be seen in the final sentence of the second paragraph extracted at para 68 above. In the circumstances, I am not disposed to view ICI Chemicals as an authority in support of the applicants' position in the present case.
73 Moving to 2004, in Novartis Merkel J said ((2004) 62 IPR at 106 [133]):
However, amendment has been refused in cases of "culpable delay". This can arise where "the delay was a deliberate ploy designed to gain some illicit advantage": Wimmera at 39,792; see also Bentley at 377. Also, if the patentee knew of the need for an amendment but failed to apply for it for a long period, amendment may be denied because "in the meantime the patentee has represented to the public that he has a valid claim when he knows it cannot be supported in its present form": Rescare at 10-11: see also Smith Kline & French at 567 and Bristol Myers at 857. The policy underlying the above observations is that "it is in the public interest that patentees should not delay in seeking to amend and that amendment will not be permitted in cases where a patentee knows or ought to know that amendment should be sought and fails to do so for any substantial period of time": Smith Kline & French at 567.
This was, perhaps, no more than a summary of the jurisprudence as disclosed by the earlier authorities, but it is noteworthy that his Honour decided the point arising under s 105 by reference to a mix of factors which included when the patentee ought to have known that the amendments should be made: see 62 IPR at 112 [162].
74 Most recently, in Apotex Pty Ltd v Les Laboratoires Servier (2009) 83 IPR 42, Bennett J accepted the following as a convenient summary of some of the matters that had been considered relevant when questions of delay arose (83 IPR at 57 [88]):
· Mere delay does not warrant refusal although the patentee must explain any delay, which should be reasonable.
· If a patentee becomes aware of the undue breadth of its claims, it must act to amend them without undue delay.
There is no support here for the categorical terms in which the applicants proposed that the matter of delay should be approached.
75 I have, with respect, found the passage from Smith Kline set out at para 64 most helpful in identifying the underlying principle which should inform the court's thinking on the matter of delay. Clearly "mere delay" is not disqualifying, and neither is delay accompanied by knowledge of the relevant prior art. But when the circumstances are such that the patentee not only knows of the prior art but has been exposed to the view that the prior art would, or might well, be fatal to the validity of the claims in question, the onus, as it were, effectively shifts to him or her (the patentee) to bring forward a reasonable explanation why inaction was preferred to amendment at that stage. The patentee is, of course, under no obligation to accept the view to which he or she is exposed, but if the view comes from a credible source the patentee will be best placed later to justify his or her inaction by evidence of serious attention having been given to the matter, ideally in the form of professional advice.
76 I consider that to restrict the circumstances in which an application to amend might be successfully resisted to those in which it was common ground, or had been established, that the unamended patent was invalid, and the applicant knew of it, would be to take a position which is altogether too categorical, and one for which there is no support in the decided cases. It must be allowed that there may be situations in which some lesser degree of a need to amend, and an applicant's actual or constructive knowledge of it, should be recognised as sufficient, with other circumstances, to disentitle the applicant to the favourable exercise of the court's discretion. A patentee who has been exposed to facts from which it was, or reasonably ought to have been, apparent to him or her that a claim might well be invalid unless amended, and who later seeks the favourable exercise of the court's discretion under s 105 is, in my opinion, in no position to say that there was, on the earlier occasion, no "need" to amend simply because it had not then been conclusively established that the claim was in fact invalid. All will depend, in my view, upon the extent and quality of the applicant's appreciation (actual or constructive) of the circumstances from which a need to amend is said to arise, and from the nature of those circumstances themselves.
77 That leads me to the fourth of the applicants' propositions mentioned in para 58 above, and specifically to the nature of the applicants' response or responses to the challenges which had been made, in foreign jurisdictions, to claims which corresponded to the present claim 1.
78 Save for some formal and chronological material, the applicants filed no affidavit evidence with respect to the difficulties which they encountered having the corresponding patents registered in the United States, Russia or Canada (or, initially, Europe). Such evidence as there was of those events was by way of the tender (by the applicants) of documents which they had provided to the respondents on discovery, and by way of the respondents' cross‑examination of Messrs Turvey and Cox. From the nature of that evidence - and perhaps more so from its limitations - I would infer that neither the applicants, nor DCC on their behalf, obtained legal advice as to the validity of the Australian claims 1 and 7 in the light of the examiners' objections in those three jurisdictions. Indeed, there is no evidence of such advice having been sought as to the legitimacy of those objections in the jurisdictions to which they respectively related. As against that circumstance, the objective facts are that, in each case, an amendment was sought. These facts provide a deal of support for the respondents' case that, at each relevant time, the applicants well appreciated that, in order to avoid the prior art, it was necessary to amend the patent applications concerned; and therefore, and correspondingly, it was necessary to amend the existing patent in suit.
79 The applicants' answer to this is best encapsulated in the following evidence given by Mr Turvey (while under cross‑examination):
There is no practice … that I'm aware of, nor have I ever received advice from my attorneys anywhere in the world[,] that once a particular amendment is made to a patent in any particular jurisdiction … there is some benefit or gain to be had in reviewing the entire portfolio with that in mind and certainly, we have never done that.
The difficulty with this approach is that it was not merely that an amendment was made in a particular jurisdiction: it was that examiners in multiple jurisdictions expressed the view that claim 1 should not be granted because of what was substantially the same prior art in each case. Whether it was lack of novelty or want of an inventive step, the applicants were squarely on notice that claim 1 was problematic, and the significance of that circumstance is not depreciated by the view of things expressed by Mr Turvey. It is here that the absence of any evidence of professional advice contrary to the opinions expressed by the examiners counts particularly against the applicants. Those opinions, in my view, imposed upon the applicants at least the obligation to obtain such advice in relation to the patent in suit, if they are now to be heard to say that nothing that occurred in the early years made it necessary for them to amend.
80 Mr Turvey also agreed with a proposition which I put to him that, if the dog were sleeping, one would not kick it, adding:
But that almost suggests that there's a conscious effort not to do that. There was no conscious effort to do anything. Once patents go to grant, they go to grant and unless there's a good reason to change them, you don't.
When I suggested to Mr Turvey that the question of an amendment "just wasn't on your radar", he responded, "it certainly wasn't". He was speaking here, of course, of the period which preceded the European post‑grant opposition proceedings (as I am in this part of my reasons). Even so, the cases seem to establish the proposition that circumstances known to the patentee, which give rise to an apparently legitimate concern as to validity of a claim, ought to be on his or her radar if he or she later moves to amend. I do not consider it to be a satisfactory response to assert that, because the patent stood on the register, the patentee did not need to take the initiative. To the contrary: the cases establish that the patentee, as the person who will have access to all the relevant information, should not wait until a challenge is made by a third party in whatever form of proceedings may be appropriate in a particular jurisdiction. Although it will always be a matter for judgment, on any view there may be a time, while the patent remains in the register free of any challenge, when the extent and quality of the patentee's knowledge will be such as to call upon him or her to take the initiative and apply to amend.
81 From at least 2001, the applicants had been aware of the significance of D1 and D2 to the validity of the patent in suit. They invite me to accept that they reasonably took the view that these citations were not fatal, but, as noted above, it appears that they had never received professional advice to that effect. As against this, in the United States and in Russia, the applicants proposed a particular amendment to claim 1 which appears to bespeak a real concern about anticipation. The same amendment was proposed in the European application, although, as I have noted, that was not carried through into the patent as granted (for reasons of which there is no evidence). To the extent that the applicants invite me to hold that they came under no obligation, as a result of these events, to consider applying to amend the patent in suit, I would be disposed to reject that invitation. I would not hold that the applicants must necessarily then have amended, but there is no evidence that they even gave consideration to the matter. That was not, in my view, a reasonable response on the part of the beneficiaries of a statutory monopoly. As it happens, however, I am not called upon to determine what course might reasonably have been adopted by the applicants in 2001, in 2003 (when the US patent was granted) or at any time before the filing of the second respondent's opposition in Europe in June 2007.
82 That opposition put in train a series of events in which the applicants were obliged to give, and did give, attention to the defence of the European claim 1 in the light of D1 and D2. The way that Mr Cox and Mr Sheard handled the applicants' response to the opposition was, in my view, timely, conscientious and responsible. It led to the making of the first auxiliary request, in which a pH range was introduced into the claim. If the applicants did not previously have mapped out for them a specific expedient to protect the relevant claims in the patent in suit from the potential of a challenge from D1 and D2, they had one then. It is also significant, in my view, that the applicants chose to make no submission in support of their main request. That circumstance tends to reinforce the conclusion - which I would in any event be disposed to reach on the evidence - that the applicants were in possession of no professional advice to the effect that claim 1 could withstand such a challenge.
83 Having filed their first auxiliary request in the European opposition proceedings in April 2008, the applicants made the very same application to amend in Canada in June of that year. That application was, of course, in response to the same prior art as the second respondent had used against the applicants in Europe. Yet still, on the evidence before me, the applicants sought no professional advice as to the validity of claim 1 of the patent in suit, nor as to the ramifications for that claim of what was occurring in Canada and Europe.
84 But the sequence of events with which I must presently be concerned does not end there. Not long after the events referred to in the previous paragraph, the applicants were given cause to believe that the respondents may be infringing the patent in suit. They engaged solicitors, and briefed them on the issues that were relevant to infringement, but still no advice was sought as to the risk to validity posed by D1 and D2, nor as to the advisability of an amendment. At his telephone conference with Mr Pascarl in November 2008, Mr Turvey (in response to Mr Pascarl) suggested that amendment should be high on the agenda, but there is no suggestion that he linked this to the events in Europe or Canada, or informed Mr Pascarl of the fact that the applicants had, in effect, a ready‑made amendment which they had found convenient to use in those jurisdictions.
85 Given the history to which I have referred, I consider that the applicants delayed unreasonably before moving to amend the patent in suit in November 2009. Clearly they were in a position to apply to amend when they received Mr Sheard's draft European amendments in April 2008. Their reasons for not doing so, either then or for more than 18 months thereafter, is that they were reasonably entitled to await the outcome of their two European requests. This is, of course, a justification now advanced by the applicants for their inaction. There is no (at least documentary) evidence that this reflected the applicants' actual thinking at the time. There is no evidence, for example, that the applicants sought or took professional advice on the timing of any amendment application in Australia, nor upon the relevance of the course followed in Europe to that question.
86 However that may be, I am in any event not persuaded that the desirability of knowing what the Opposition Division thought both of the validity of the unamended claims, and also of the potential of the amended claims to meet the challenge presented by the prior art, is a sufficient discretionary ground to justify, for the purposes of s 105, the applicants' inaction over the period to which I have referred. The suggestion that it was reasonable to await the Opposition Division's opinion on the validity of claim 1 in its unamended form is, in my view, belied by the choice which the applicants made not to offer any submissions on that subject. Particularly having regard to their earlier experience in the other jurisdictions in which D1 and/or D2 had been cited against them, they could not realistically have anticipated that, without any submissions in support, the validity of claim 1 in its unamended form would be upheld in the Preliminary Opinion. Indeed, Mr Sheard's proposal that the main request would be retained "simply to give flexibility in the event of an appeal" strongly bespeaks an anticipation that the Preliminary Opinion would be adverse in relevant respects. Neither do I consider it reasonable for the applicants to have held back from moving for any amendment in Australia until they received, in effect, a quote from the Opposition Division as to the sufficiency of the proposed pH amendment to meet that challenge. The applicants were (and are) under no obligation to amend the patent in suit, but, as Aldous J said, if they were going to amend, they ought to have done so "promptly". The gravity with which they clearly viewed the circumstances in Europe, and the attention they gave to the terms of an amendment, made it unreasonable, in my view, for them not then to have applied in Australia, whether or not they had received the Preliminary Opinion of the Opposition Division.
87 However, I am not required to decide the present motion even by reference to the circumstances and considerations to which I have referred so far. That is because the applicants did not merely await the Preliminary Opinion of the Opposition Division: on 10 March 2009 they commenced the present proceeding, in which they alleged that the respondents had infringed the unamended patent. That was, in my view, to take unfair advantage of the patent within the meaning of the fourth principle of Aldous J. The applicants, even then, might have accompanied their proceeding with an application under s 105. They took no such course. They were content for the present proceeding to be determined by reference to a claim which they had found it necessary to amend elsewhere, and for which they offered no real defence in the European Opposition proceedings less than 12 months previously. And there is no suggestion in the evidence that the applicants sought professional advice on the appropriateness of the course which they then followed.
88 Considering the history of the applicants' experiences with the patents, and patent applications, which flowed from the original PCT application in 1997 - not as a collection of isolated events, but as a continuum against which the applicants' actual or constructive knowledge of the need for an amendment might be inferred - I am of the view that November 2009 was too late to make the present application to amend, particularly having regard to the applicants' choice to sue on the unamended patent in March 2009. I say "too late", of course, not to imply a view that the conduct of the applicants was reprehensible, but merely in the sense that the history of inaction to which I have referred places the applicants in no position to seek the favourable exercise of the court's discretion under s 105. Having chosen not to amend for so long, having omitted to obtain professional advice on the appropriateness of amending, and having decided to sue on the unamended patent, the applicants should, in my view, be obliged to prosecute the present proceeding against the terms of the relevant claims as they stand.
89 There are only two circumstances which have caused me to pause before reaching this conclusion. The first has already been mentioned: the fact that it has not yet been established - and it may never be established - that the claims in question are invalid against the prior art relied on by the respondents. Having a registered patent in Australia, why need the applicants have amended here just because examiners in some other jurisdictions took a particular view based on the prior art? The answer to this question, in my view, is that the examiners' views are significant not merely because they constituted hurdles which the applicants had to surmount in the jurisdictions concerned. They are significant because they provided the occasion - several occasions, as it happened - for the applicants to have been required to give attention to prior art citations which were obviously relevant also to the validity of the patent in suit. The focus with which the problem ought reasonably to have presented in the applicants' eyes was sharpened by the filing of, and by the applicants' response to, the second respondent's opposition to the European patent. It is no answer to the proposition so clearly implied by these events to say that, because the patent in suit was on the register, it did not need to be amended. If anything, the contrary.
90 The second circumstance is that the respondents make no claim to have been prejudiced by the applicants' omission to make their present application in a more timely way. In a number of cases, the absence of prejudice has been mentioned as a circumstance favouring the making of an amendment, and I accept that it should be so regarded. The cases have, however, referred also to the public interest. I have mentioned elsewhere that the patent in suit gave the applicants an ostensible statutory monopoly. To the applicants' actual or constructive knowledge, serious and apparently legitimate issues had been raised elsewhere which had the potential to undermine the validity of the relevant claims in the patent. It was, in my view, strongly in the public interest that those issues be confronted in the Australian context. It was not in the public interest that they be ignored, and that proceedings be commenced on the silent premise that they did not exist. I do not consider that the absence of prejudice on the part of the respondents is any sufficient counterweight to the public interest considerations to which I have referred.
91 For the foregoing reasons, I propose to grant the applicants' motion to the extent only that it relates to the amendment to correct the typographical error to which I referred in para 2 above. Otherwise, I shall refuse the motion. I shall hear the parties on the question of costs.
I certify that the preceding ninety-one (91) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Justice Jessup.