Peterson Energia Inversora & Ors v The Argentine Republic

Thursday, 15 January 2026 MR JUSTICE WAKSMAN

1. I have come to a clear view about this. I will give my judgment now. There are two applications before me.

2. One is for permission to adduce expert evidence of Argentinian law in relation to a hearing at which the defendant, the Republic of Argentina, seeks to challenge the jurisdiction of this court to enforce and recognise a decision of the second district of New York; by that decision, the Republic was ordered to pay to the claimants, who are minority shareholders in a company called YPF, about 50 billion USD by way of damages. In relation to that matter, the claimants, which I shall refer to as Petersen, have brought proceedings to enforce and recognise that judgment here.

3. There has been fixed since early August of 2025 a hearing to deal with the Republic’s jurisdictional challenge to any such enforcement, over five days in 2026. The time allowed for the hearing took into account the giving of evidence by experts on Argentinian law including, if necessary, their cross-examination.

4. The second application before me which was expressed by the claimants' solicitors to be as a response and an answer to the application to adduce expert evidence on Argentinian law, was made on 24 November 2025, and by that application Petersen seeks to bifurcate the matters to be dealt with at the May 2026 hearing so that out of a total of six issues, issues 1, 2, 5 and 6 and part of issues 3 and 4, will be dealt with at that hearing but the remainder will be dealt with at a separate hearing, if necessary.

5. The matters which are to be deferred, according to what I shall describe as the bifurcation application, are those parts of issues 3 and 4 require, according to the Republic, the expert evidence on Argentinian law.

6. So far as the expert evidence application is concerned, the submission of the Republic, having regard to fact that under Part 35 any expert evidence must be reasonably required, is either that the expert evidence is necessary for the determination of the relevant issues, or even if it is not necessary, it would assist the court in determining the relevant issues and that there are effectively no counter-arguments to the admission of such evidence.

7. I need to say something about the background which I take principally from the Republic's skeleton argument. I do not believe any of it to be controversial.

8. The case in New York resulting in the judgment which Petersen seek to enforce here concerned a decision in 2012 of the Argentine government to expropriate 51% of YPF, a strategic energy company incorporated in Argentina. The Republic did so without first making a tender offer for the shares of the minority shareholders (ie the claimants). The claimants say that was wrong, and they brought proceedings for damages for breach of contract in the Southern District of New York federal courts (“the SDNY”). It was their success in that claim there which led to the judgement sought to be enforced here.

9. The substantive judgment was given in 2023. There is a pending appeal which has been heard but where there is no decision as of yet. Of the various jurisdictional challenges to be heard here in May of 2026, the relevant challenges under issues 3 and 4 are first, that the SDNY judgment cannot be enforced here because it would be contrary to English public policy, and secondly, and in any event, the Republic is entitled to state immunity in respect of this present claim to enforce that judgment. I will say a little more about those particular challenges in due course.

10. The proceedings here commenced by Petersen on 4 March 2024. On 13 December 2024 the Republic filed its jurisdiction challenge. At the same time and by the same application it sought to adduce expert evidence on Argentine law in the form of three reports from by three professors, including Professor Alfonso Santiago, which had originally been filed in the SDNY proceedings.

11. From that point onwards, I am satisfied from the correspondence the Republic sought to engage Petersen on the question of the admission of Argentine law expert evidence for the purposes of the jurisdictional challenge. In short, Petersen did not agree that this evidence should be admitted.

12. What subsequently happened was that on 7 October 2025, there having been no resolution as to the question of the admission of the expert evidence, the Republic wrote to Petersen and enclosed a CPR Part 35 compliant copy of a report by Professor Santiago which sought to address eight particular questions. The report is about 42 pages long and has an initial summary section of about six pages, where he expresses in the form of an executive summary what his answers to those questions are.

13. That was then objected to by Petersen on 27 October. Because of that, the Republic made an application to adduce expert evidence on foreign law on 14 November which effectively sought to recast the application originally made on 13 December 2024. As I have already indicated, it was said to be in response to that further application that on 24 November Petersen made the bifurcation application.

14. Although the bifurcation application suggested in part that the bifurcation going forwards should postpone the question even of deciding whether expert evidence on Argentine law should be admitted at all until after the hearing in May, that submission was not advanced to me today.

15. As Mr McGrath KC has helpfully indicated today, while Petersen continue to resist the case for the admission of any expert evidence on Argentine law and he has helpfully indicated that in the course of his submissions, his primary focus has been on the bifurcation application.

16. I will deal with for the application for the admission of the expert evidence first and then I will deal with the bifurcation application.

17. To say a little more about the background, YPF started as a state-owned company in 1922. It was privatised in 1993. Its foundational document consists of its bylaws which are governed by Argentine law.

18. There were two provisions of importance. First of all, section 7 said that anyone wishing to acquire, whether directly or indirectly, a percentage of the class D shares had to arrange a takeover bid for the acquisition of all of the remaining shares. In other words, the other shareholders would have an entitlement to be bought out, and there was a detailed mechanism for that to take place.

19. Section 28 is then addressed specifically to the Republic of Argentina, stating that if there was to be an acquisition of at least 49% of the shares by the Republic, then section 7 would apply to that acquisition. In other words, there would then have to be the tender offer for the acquisition of the other shares which I have just described.

20. The position at the relevant time was that the Petersen group had acquired about 25% of YPF shares and the other claimants had acquired about 3%, and the balance was held by the oil company Repsol, therefore more than 51%. A decision was taken by the Republic that it was necessary effectively to take over the company because of the concerns it had about its performance. That was its perception. And under Article 17 of the Republic's constitution as well as a general expropriation law, its Congress, that being the legislature of Argentina, had the power to authorise the expropriation of assets in the public interest with a scheme for compensation to be paid to those whose assets were expropriated.

21. The Republic gave detailed consideration given to this, there was a deliberate choice taken by the Congress and publicised at the time that the Republic was not going to go down the Article 7 route, as it were, of making a takeover bid for the other shares; but rather it was going to use its powers of expropriation and expropriate the 51% of YPF's shares held by Repsol and it did together with the acquisition of certain other shares of relevant Repsol holding companies. And there was a law enacted to give effect to that expropriation which was said to be in the public interest.

22. The mechanism for compensating Repsol as a result of the expropriation of its shares was carried through and there was a settlement of 5 billion USD.

23. The proceedings in New York were brought by Petersen on the basis of various contractual obligations, in particular in relation to the listing obligations of any tender offer which would have had to have been made by the Republic but was not made, they say, in breach of Article 7 of the bylaws. Some of those obligations had to be performed in New York, And therefore the federal courts of New York had jurisdiction to deal with that contractual claim.

24. There are two particular aspects of the New York proceedings which I need to mention. First of all, there were interlocutory motions to dismiss brought by the Republic on the grounds that, among others, all of this was effectively inviting the New York court to pronounce upon the acts of another state, and that, like the public policy rule here, was not a matter which it was open to the court to do.

25. Secondly, there was a reliance upon a US statute concerning state immunity that they said was infringed, the US Foreign Sovereign Immunities Act, and there were other points taken as well including, for example, those dealing with forum non conveniens.

26. Those interlocutory motions were dismissed by the First Instance court in SDNY, and although there was an appeal to the Second Circuit Court of Appeals in 2016, in 2018 the Second Circuit Court of Appeals upheld the original court's dismissal of one of the grounds for challenging the jurisdiction in relation to the Act of State Doctrine. A second ground of state immunity was found not to have been necessary to be decided at that point, but the upshot was that the jurisdiction challenge at that stage was refused.

27. It is worth noting that the judgment of the Second Circuit Court of Appeals did refer in one part to some expert evidence on Argentinian law which had been furnished by the Republic, although it disagreed with it. Although as Mr McGrath KC points out, there were large parts of the Second Circuit Court of Appeals’ judgment which did not refer to expert evidence at all, it is right to point out that for the purpose at least of that appeal, and I think at first instance, both sides put in expert Argentine evidence relating to jurisdictional matters as opposed to the substantive matters which were dealt with later on.

28. There were some attempts to revive some parts of the jurisdictional challenge in the New York proceedings but they failed, and ultimately the judgment of 2023 was produced on the substance of the claims, finding that the Republic had been in breach of Article 7 and awarding compensation in total of something over 16 billion USD. There is an appeal pending on the substantive decision, and oral argument was heard on 29 October 2025 but no one is now suggesting that the matters before me should be adjourned to await the result of that appeal.

29. For the purpose of the matters before me today there have been witness statements filed by both sides from the solicitors: a fifth witness statement of Konrad Rodgers of 14 November; a first witness statement of Fiona Huntriss of 28 November; a sixth witness statement of Konrad Rodgers; and there is also a summary of conclusions taken from the draft expert report of Alfonso Santiago.

30. At this stage it is necessary for me to say a little more about what have been characterised as the substantive parts of issues 3 and 4 for the May 2026 hearing.

31. The first argument made by the Republic is based on the fact that, as is common ground, any judgment to be enforced here must not fall foul of public policy because the courts will not enforce judgments which as a matter of public policy they should not.

32. There is a strand of public policy here which says that courts here should not give judgment on and pronounce upon what are the acts of foreign states. What is then said is that it would equally be a breach of public policy if the court whose judgment is sought to be enforced here itself pronounced upon and gave judgment upon the acts of foreign states, because to allow the judgment to be enforced in those circumstances would equally be a breach of public policy.

33. There is a preliminary point taken by Petersen in relation to that; it says that effectively you cannot transpose to the court whose judgment is to be enforced here that public policy requirement and that there is a difference between the function of a court here when in substance it seeks to give judgment on the act of a foreign state as opposed to its role when enforcing the judgment of a court elsewhere .

34. That is a preliminary point which is resisted in turn by the Republic. The substance, however, is as I have indicated. And what is then said is this: that what the US court was indeed doing, although it held that it was not, was to make a judicial decision about the act of a foreign state, namely Argentina. And the act concerned was either a decision made or legislation which was passed in Argentina.

35. It is common ground that a central question for the jurisdiction challenge, which is whether the relevant impugned act was in truth an act of the relevant state acting qua state, namely in its sovereign capacity, or whether in distinction to that it was acting in a commercial capacity.

36. The public law, public policy objection, if transposed, would apply only to the former and not to the latter. In support of that argument the Republic's contentions in summary are that the relevant bylaws to which I have referred were superseded and in effect extinguished by the expropriation law which was passed. And so there was never, once the acquisition had been made, any private right remedy remaining, and that therefore while a claim was made on the basis of the contractual provisions, if they had been subsumed into and abrogated by the act of appropriation, the only act that can be relevant was the expropriation legislative acts themselves which both sides accept are sovereign and not commercial in character.

37. In order to support that argument the Republic contends that under Argentinian law there would be no distinction between the underlying decision to expropriate and then the non-acquisition of the shares of the minorities by tender. And the Republic contends that as matter of Argentinian law that would be one overall act of state.

38. If that is right, the Republic goes on to contend that when characterising the relevant act for the purposes of the public policy act of state principle it could only be characterised as a sovereign act and not commercial act, in which case that public policy exception would be fatal to the jurisdiction of this court.

39. Section 28 of the bylaws is relied upon to the effect that it is applied specifically to the state, and therefore is itself only concerned with acts of the state and in sovereign character.

40. Now, all of that is hotly disputed by Petersen. Petersen says that as a matter of interpretation. while the expropriation is one thing, the failure to comply with contractual obligations which on their case still subsist is quite another, and it is the latter which is and should be the focus of the relevant act of state.

41. It also says, for example, that Section 28 of the bylaws in fact supports its case because it should be read as saying that even the state, if it is acquiring not less than 49% of the shares, should be governed by the same contractual buyout process as with any other acquirer of the shares. And Petersen argues that it is not correct simply to look at the entirety of the acts and characterise them as one overall sovereign act which would then exclude the possibility of there being a commercial act which would, if correct, disapply the public policy objection.

42. All of that is brought in under section 31(1)(a) of the Civil Jurisdiction and Judgments Act of 1982, which is the governing statute here.

43. The second argument is more specific in this sense. Section 31(1)(b) of the 1982 Act is also said to be engaged because it then invokes relevant provisions of the State Immunity Act of 1978. It is not necessary to go to it, but the point that is being made is that Argentina, in relation to the claim to enforce the judgment here, is entitled to state immunity.

44. So far as that is concerned, it is common ground that it would be necessary for Petersen to displace the existence of immunity here to show that one of two exceptions applies. The first exception under section 3.1(a) of the State Immunity Act says there will not be immunity if the proceedings are about a commercial transaction entered into by the relevant foreign state. And so that of course reflects the sovereign/commercial distinction that is also in play in the first public policy argument.

45. There is a second exception which says that it will not apply to proceedings in connection with the contractual obligation of any kind to be performed wholly or partly in the UK. Petersen argues that the proceedings are here to enforce a judgment in relation to what happened in the US and the obligation was to be enforced in the US and the US should be treated as the UK for these purposes.

46. There is in fact, however, an exception to that exception; in other words, there will still be immunity if the contract was made in the territory of the state, ie Argentina, and the obligation in question is governed by its own administrative law.

47. The Republic says that that exception to the exception applies and that itself is a matter which also engages questions of Argentinian law.

48. So underneath the overarching distinction in issue as to whether the action be characterised as commercial or sovereign which, is a matter for the English court applying the English rules, there are the subsidiary arguments to which I have referred.

49. Another important preliminary point which has been taken by Petersen is that in any event the state immunity argument and the public policy argument, if they were otherwise runnable, are in fact not open to the Republic because of an issue estoppel created as a result of the interlocutory decisions of the SDNY which dealt effectively with the same arguments in the contexts of the motions to quash the proceedings there.

50. But that issue is itself hotly disputed. The Republic say in brief that issue estoppel of the foreign court can only run if the judgment of the foreign court by which the estoppel is invoked, and here prima facie the only judgment sought to be enforced is the final judgment, is if that judgment itself can be recognised. In other words, it is a bootstraps argument. In other words, if the judgment will not otherwise be recognised, the issue estoppel will not help. If it is otherwise to be recognised, it is not necessary.

51. The counter argument to that, which is made by Petersen, is that that fails to give weight to the distinction between the judgment sought to be enforced here, which is the substantive judgment of 2023, as opposed to the earlier judgments which were interlocutory in character. And the debate goes on because the Republic responds to that by saying they are not decisions which have been sought to be recognised here.

52. That is sufficient to indicate the scope of the issue estoppel argument.

53. What has happened in relation to the underlying application for the Argentinian evidence is that in my judgment it has become quite focused. I say that for this reason. First of all, we now have had since October a draft of the actual expert report which is to be relied upon by the Republic if it gets permission. It is not clear at the moment as to whether all aspects of that report are in dispute. The first three questions for that report raise matters of the general position in relation to private and public law in the Republic. I would be surprised if ultimately there was a dispute, but at the moment we are not told what Petersen's position in relation to it would be.

54. What has then happened is that the eight questions which have been asked of Professor Santiago and which he has answered in his draft report have then been put to Petersen as defining the limits of the expert evidence to be adduced. And although Petersen continues to resist in full the application to adduce the expert evidence, it has helpfully commented upon a table produced the Republic explaining what the questions are, why the Republic says they are relevant and should be admitted as expert evidence, and now why Petersen say they should not be.

55. That is the central way in which I propose to look at the expert evidence application, but I should make some further preliminary points. First of all, it is clear from the authorities that in relation to these sorts of challenge, context is very important and the court should be shown all the relevant context.

56. The second point is that in relation to context, Mr McGrath KC says that this is all well and good, but these matters essentially only concern the factual context to the decisions to be considered and characterised by this court. However, I do not see why context should be so limited, and indeed it has not been suggested to me that as a matter of principle Argentinian law evidence cannot be relevant to the issues such as this. Rather, the point is made that they are not relevant in this particular case, because they do not assist, and in any event the questions which have been formulated for the experts are inadequate for reasons which I shall go on to explain.

57. I should add that although it is not a matter for me to decide now, I do note from my reading of the decision of the Court of Appeals in the SDNY, there was a considerable focus placed upon what the gravamen of the claim was being made by Petersen actually was; in other words, Petersen claimed to be concerned only with the enforcement of its private rights and was not claiming to attack the expropriation decision as a matter of public law.

58. It seems to me, although it makes no difference to my decision, that the process of analysis here on such questions is somewhat different because it is not simply a matter of looking at the claim even in the context of the responses to it, but rather the exercise of characterising overall what the underlying act concerned was, regardless of how one party or other may put its case about it.

59. Turning then generally to the question of the application of Argentinian law, the overarching point made by the Republic is that it is relevant and necessary or at least will assist the judge because it explains how public and private law rights interact. It explains the process of expropriation, both in general terms and in terms of the expropriation law passed here, and how on the Republic's case it affects pre-existing private law rights in the same arena, if I can put it in that way. And I have explained the notion of how the expropriation as a matter of Argentine law is said to affect the private rights effectively by extinguishing them.

60. Now, in relation to the general points Mr McGrath KC submissions in my judgment to a significant extent concerned why Petersen contends that those arguments are simply wrong. Well, they may or may not be. It is not a matter for me. The question is whether Argentinian expert evidence on the law can properly be invoked in relation to them.

61. What is said secondly is when one looks at the report of Professor Santiago, he is trespassing impermissibly into the ultimate questions which will have to be decided by this court on the jurisdictional challenge.

62. So he says that for Professor Santiago to explain that under Argentinian law in his opinion the effect of the expropriation is to abrogate the private law rights is impermissible and that is something only for this court to decide. As I see it at the moment, that is not correct.

63. First of all, it has been made clear in a number of authorities that the courts have to look at the expert evidence in its particular context, and the defendants have referred to the helpful dicta of Lord Justice Evans in relation to that matter. He said in MCC v Bishopsgate Investment [1999] CLC 417 (CA) {DHH/9/1}, the function of the expert witness on foreign law is summarised as informing the court of the relevant context of the foreign law, identifying statues and other legislation, explaining where necessary the foreign court's approach to their construction, identifying judgments or other authorities, and where there is no authority directly in point, to assist the English judge in making findings as to what the foreign court's ruling would be if the issue were to arise for decision there.

64. Of course, as Mr Justice Calver said in a subsequent case, that does not mean that the expert should be seeking to impose on this court his or her personal views as to what the foreign law should be. But I do not detect any of that in Professor Santiago's report. And by way of example, in Tullow Uganda v Heritage Oil [2013] EWHC 1656, Mr Justice Burton cited the dicta of Lord Justice Evans when admitting evidence as to whether certain notices of tax assessment were: "... valid under Uganda law, or strictly whether a Ugandan court would hold such notices to be valid. The notices were unique to the facts of that case but nonetheless foreign evidence was admissible on their likely treatment."

65. That seems to me to be analogous to the position here, because what Professor Santiago was doing is to say on analysis how the private act would be dealt with in the light of the expropriation.

66. In any event, that is not the ultimate question. The ultimate question for the court is what the relevant acts were and whether they were commercial or sovereign in character.

67. So I do not accept the general objection that the evidence sought to be adduced is objectionable in that way. If there is any residual point to be taken about that, it can be taken at the ultimate hearing. That is my view on the position as we see it today in relation to this application.

68. A related point is that not only should the expert evidence be confined to what are the principles of the foreign law, that those principles should be articulated. Petersen says that they have not been. So far as that is concerned, having read Professor Santiago's report with some care, it seems to me that they are. But lest there is something further to be said, if this evidence were to be admitted then I would be directing that there is a period during which Professor Santiago is obliged to state whether there were any other principles of Argentinian law that he relies upon and in that way if the expert evidence was to be admitted the two expert reports would not be passing like ships in the night.

69. Those are my answers to the general objections which have been raised here by Petersen.So dealing with the eight particular questions.

70. Question 1 is to: "Describe the general framework of Argentine law with respect to the interaction between public law actions and private law rights." Question 2 says: "Describe the legal basis for each of the steps taken ... concerning [the acquisition for the 51%] in 2012-2014. Specifically, describe the basis for (a) the expropriation of assets generally; and (b) the expropriation process which led to the [particular acquisition]."

71. Pausing there, the Republic says that these are relevant because they addresses the background to the Republic's position that its actions were sovereign ones, within the framework of Argentine public law, which overrode any private law rights and the framework of the impugned actions which are the subject of the SDNY judgment and relevant to the issue of whether they constituted a sovereign act, and this bears upon the commercial or sovereign distinction.

72. Now, the simple point made by Petersen here is there is no issue as to whether the expropriation was a sovereign act. But that does not mean that the questions are inapposite, because it depends on whether these building blocks of the distinctions between private and public law in the way that they have been expressed by Professor Santiago are in fact agreed and there is no indication. I suspect that they will be, but at the moment I consider that those two questions are valid for the purposes of expert evidence.

73. Question 3 asks: "As to the location of the legal steps taken ... further to Question 2(b) ... by the Government of Argentina ... were they performed within the territory of Argentina and, where taken by the legislature did they take placed within Argentina?”

74. This is said to be relevant because of the tests set out in the recent case in the Supreme Court in the Maduro case as to the territorial limb of the foreign act of state test.

75. Question 3 is not been addressed in the context of Questions 1 and 2. If in fact the answer to it is agreed, then there is no problem. But if it is not agreed then in principle I consider it would also be appropriate for the question of expert evidence.

76. Questions 4 and 5 really go to the heart of the matter.

77. Questions 4 says: "As a matter of Argentine law, are the following considered to be a single legal endeavor: (a) the decision to expropriate ... and (b) any decision not to compensate ..."

78. Question 5 says: "As a result of the ... actions ... did any private law rights accrue to the Claimants under ss 7 and/or 28 of the Bylaws ..."

79. And I have explained already what the issue is there and that in my judgment Argentinian law is relevant to those questions.

80. I interpose to say here that Mr McGrath KC at one point in his submissions said this is not a case as if it is being said that there is some peculiar aspect of the Argentinian law of contractual construction which is so significantly different from the English law of construction that there needs to be Argentinian law evidence adduced on it. I accept that, but I do not accept that that means that Argentinian law is not otherwise relevant.

81. Petersen says that Questions 4 and 5, were precisely the issues which the SDNY court determined in C's favour. Tat may well be right, but (subject to the issue estoppel argument) the issue here is whether Argentinian law evidence is relevant for the purposes of the jurisdiction application here.

82. In my judgment, questions 4 and 5 are both apposite for expert evidence. See in particular the particular passages of Professor Santiago's report dealing with those central issues at paragraphs 53, 56, 60, 64 and 69.

83. I also reject the suggestion that the questions do not sufficiently or properly articulate the issue for the experts to opine upon. It seems to be straightforward in the way that it has been answered by Professor Santiago, not that it is necessarily correct, but I do not see that there is any difficulty for any expert opining on answers to those particular questions.

84. Question 6 asks: “What was the effect of the steps mentioned in question (ii) above with respect to any potential or accrued private law rights of the Claimants concerning the YPF shares? Specifically: (a) are the rights asserted by the Claimants in the US litigation under Articles 7 and/or 28 of the Bylaws consistent with Argentine public law; and (b) do the Claimants retain any rights under Articles 7 and/or 28 of the Bylaws following the expropriation of 51% of the YPF shares?”

85. In my judgment and in the light of what I have already said about the preceding questions, these are plainly matters of Argentinian law and are relevant.

86. Question 7 says: "... what recourse, if any, did minority shareholders ... have in these circumstances."

87. That is really simply a follow-on from question 6. It is a logical extension to it and I also consider it is appropriate. Question 8 says: "Where did any obligations under s28 of the Bylaws fall to be performed?"

88. This is a question of performance of the underlying contract if those obligations continued to have effect, and the question there is whether the obligations were simply in Argentina or also in the US.

89. It has been submitted to me by Mr McGrath KC that it is not really clear what the Republic's case on this is and therefore it needs some further particularisation. But I am satisfied that the way that the matter has been put is clear enough in Professor Santiago's report, and it can be appropriately answered without any real difficulty by any opposing expert.

90. And, again, in relation to the question of how the obligations were to be, and where they were to be performed, although Mr McGrath KC says that it is obvious if you look at things, it seems to me that Argentinian law is relevant here and expert evidence is appropriate to deal with those questions.

91. It may be, apart from questions 5 and 6 and perhaps even with questions 5 and 6, that there will not be much disagreement on these issues. What I am quite sure about is that they are properly articulated as they stand at the moment, and indeed no competing questions have been put before me for my consideration should I decide in principle that expert evidence is admissible.

92. For all those reasons I am quite satisfied first of all that Argentinian expert evidence is relevant and admissible on the four questions to which I have referred. Nor do I consider that the expert report proffered is lacking in terms of its references to underlying Argentinian law principles.

93. So far as the British Airways case and CPR 35 are concerned, first of all I take Mr Railton KC's point, which is that in making all these general submissions about all these various Acts and legal provisions in Argentina, without any reference to the Argentinian law position on it would make life difficult for anyone making those submissions, and I agree with him.

94. It seems that the parties in New York took the same view. Even the court did not make much reference, the expert evidence, they both felt that it would assist their positions to some extent and on that basis, this expert evidence were necessary.

95. But if I was wrong about that, then I am very firmly of the view that this expert evidence would undoubtedly assist the judge dealing with the jurisdiction application here. If I put myself in that position I would personally find it of great assistance to have an Argentinian law exposition of those particular questions to assist me in making my final determination of the relevant arguments.

96. There are under the British Airways test no counter arguments. This is not going to disrupt any trial. This has already been provided for in the hearing. It is of a narrow compass and it can all be dealt with adequately before the hearing concerned, and indeed that hearing expressly contemplated that that evidence would be or might be given.

97. For all those reasons, I accede to the expert evidence application with the proviso, subject to further argument about directions, that there should be an opportunity, a short one, given to the Republic for Professor Santiago to put forward any other principles on which he relies which have not already been articulated in the report which is before me.

98. That leads on to the question of bifurcation with which I can deal shortly. The first point to note about it is that the application was made very late, given the whole question of expert evidence had been ventilated from the end of 2024 afterwards. Lateness itself of course is not fatal. It is not suggested it is going to cause any undue prejudice in the sense of timetabling if the application were allowed. But it does perhaps indicate that what are now said to be very clear and obvious reasons why there should be bifurcation were not ones which occurred to Petersen for at least a year.

99. Secondly, I deal with the principle point made by Mr McGrath KC who candidly accepts that he is not saying that the issues attracting expert evidence cannot be dealt with within the timetable for the existing hearing.

100. So this is not a timing or logistics point which has given rise to this bifurcation application. What he says is that if one looks at the six issues which arise on the jurisdiction application, then some or all of them may be dispositive in the sense that they would obviate the need to have the substance of the public policy or state immunity arguments dealt with at all, and with that substance would be removed any expert evidence in relation to it.

101. So first issue is whether the SDNY court was competent to give the judgment it did on the basis that the Republic was present, and Mr McGrath KC is right to say that if Petersen cannot establish that the public was present in the required sense, that is the end of the recognition application.

102. Secondly and similarly, whether the court was competent to give its judgment on the basis the Republic submitted to its jurisdiction. Again, if that cannot be made out then it would be dispositive in favour of the Republic. And I will come back to items three and four in a moment, but on items five and six it is also said that as a point that is being taken as to whether there were assets in this jurisdiction, or a real prospect of a legitimate benefit, that is a point also being taken by the Republic. If they succeed on that, which relates to service out, that is the end of it and the same on full and frank disclosure.

103. On the other side, on what I here refer to as issues three and four, there are the two preliminary points to which I have already referred which Petersen contends if successful could knock out the substance of those arguments.

104. One is whether you can transpose the public policy Act of State doctrine, as it were, to the court whose judgment is being sought to be enforced. That is one point. And that would go to the public policy objection; it would not go to the state immunity objection. But then secondly, was there the issue estoppel, and if there was, that would deal with both objections. And if that is right then either or both of those objections would end there.

105. It is tempting, looking at the analysis in this way, to say that because there are these matters which are dispositive, that is a very good reason for bifurcation here. However, I disagree. Whether there was bifurcation or not, there were always going to be those issues, each of which may or may not have been dispositive in the end result. That is a common feature of jurisdiction challenges.

106. In some cases, like Hulley , the particular objections may be of such a size or complexity that it may make sense to split them up. But I do not agree that this is that kind of case at all, and it is shown not to be such a case by virtue of the fact both sides have agreed that the full exploration of all six issues can be dealt with in five days.

107. The reason why the fact they may be dispositive is not a good enough reason for bifurcation here is clear from the following further points.

108. First of all, in relation to the issue estoppel argument as a preliminary point, the first part of three and the other element about whether the public policy objection can be transposed, none of that can be sensibly dealt with absent a very full explanation of and introduction of the underlying matters of dispute here, and in particular the whole question of what it is said the Argentine state did or did not do and what the effect of the exploration was or was not. That is because until those preliminary points have been set out in some detail, it is impossible then to do the analysis of working out what it was that the SDNY did with those points, which is vital if there is to be an argument that they decided the same points that are being run here, quite apart from the other aspects of issue estoppel.

109. The same thing occurs in relation to full and frank disclosure, because that relates to the public policy argument and that in itself will have to be set out and explained.

110. That explains why it is not correct simply to say that there can be no duplication of costs or time here. There would be, because if in fact the second hearing on the substance of issues three and four was necessary, the judge dealing with that, who may very well not be the same judge dealing with the May hearing, is going to have to have all of those background matters set out and explained and consider them all all over again. That means that inevitably, if there were two hearings, there would be duplication of time and costs, and I have not the slightest doubt that the costs of two hearings would be considerably more than the cost of one hearing dealing with all of these matters.

111. The next point is that if, as Petersen says, it is prepared to “grasp the nettle” in relation to at least some aspects of issues three and four, why should it not grasp all of it? And indeed, I have to say if I was dealing with this matter having had all of these matters explained to me and having had all of the points on issue estoppel explained to me and having known at least what the scope of the expert evidence might be, I would find it odd not to be asked to go on and decide the substance of the points which, so far as the expert evidence is concerned, are really of very short order indeed.

112. In my judgment, looking at the case as a whole, which of course is a jurisdiction challenge, in relation to a judgment of some 16 billion USD it is completely disproportionate to hive off a part of the challenge which might very well, although I accept not inevitably, be decisive of the issue, to a further hearing, especially in circumstances where that hearing was fixed by agreement with the parties back in August when neither side took a point that there ought to be in any way any kind of splitting up of the issues.

113. So for those brief reasons I am quite satisfied that the bifurcation application should be refused. RULING ON COSTS

1. So far as the principle is concerned, despite the arguments very attractively made by Mr Sonecha, I do not think it would be right to reserve the costs here.

2. First of all, it does not really assist Petersen to say that their bifurcation application was made in response to the expert evidence application so as, in effect, to relegate it in this sense to a mere incidental case management decision. It was an application that specifically had to be made. It was supported I think by evidence and formed a discrete application, although connected with the expert evidence application, that had to be dealt with today.

3. So far as the argument that it may be that at the May hearing the court will be invited to say it is not necessary to decide the substance of the public policy and state immunity arguments if it upholds the issue estoppel argument, the fact of the matter is that the expert evidence will have been adduced. It will be a matter for the judge at such a hearing to say whether the judge is not only going to decide the issue estoppel point, but that in any event even if there had been no estoppel to decide the substance point.

4. So far as the set-off point is concerned, although Sir William Blair in the case cited reserved the costs there in what he described as an exceptional case, although it had certain similarities with this case, I do not for my part see that this is relevant here. The real question is when those costs should be paid.

5. Therefore, in my judgment the correct order is that the costs incurred by the Republic in resisting the bifurcation application are their costs to be paid by Petersen on the standard basis and to be the subject of a detailed assessment if not agreed.

6. However, to deal at least in part with the set-off argument, I will also order that those costs are not to be paid until the determination of the jurisdiction application.

7. I will also say, because it is not clear at the moment whether the jurisdiction application will be determinative entirely of the claim for enforcement, it looks as if it will be, if it turns out that the jurisdiction application is not the end of the matter, then Petersen will have permission to apply to extend the period for payment until the dismissal of the claim itself.

8. I hope that is tolerably clear and thank you both for your submissions. ______________