Russia sought Wednesday to block former Yukos Oil investors from enforcing an almost $60 billion arbitration award, telling a London appeals court that English courts must consider its claim to state immunity afresh.

Russia argued in the Court of Appeal that a lower English court was wrong to dismiss its claim to state immunity based on the ruling of a Dutch court, contending that English judges must not rely on foreign courts on the issue of immunity.

Vernon Flynn KC of Brick Court Chambers, representing Russia, said an English court "must determine for itself, essentially de novo, whether an applicable exception to the state's adjudicable immunity arises."

"An obligation to give effective immunity ... may only be satisfied by an autonomous determination, applying the civil standard, of the factual and legal arguments said to give rise to immunity," Flynn said. "The conclusion based on issue estoppel arising from a foreign judgment is not a determination at all and certainly not one to the civil standard."

Russia made the case at the Court of Appeal as it takes another shot at arguing that it has state immunity from claims brought on behalf of former investors of Yukos, which was Russia's largest oil company before it collapsed in 2006.

The award was more than $50 billion when it was awarded by an arbitration tribunal in The Hague under the international Energy Charter Treaty of 1991, but had accumulated around $8 billion in interest by the time the case went before a High Court judge in 2023.

The arbitration tribunal made the award after concluding that Russia had breached the treaty by engaging in an illegal campaign to bankrupt the oil company, according to an earlier High Court ruling.

Three companies, Hulley Enterprises Ltd., Veteran Petroleum Ltd., and Yukos Universal Ltd., are bringing a claim against Russia to enforce the arbitration award on behalf of investors.

Judge Sara Cockerill concluded in that 2023 High Court decision that Russia could not re-run arguments about state immunity that had already been rejected in the Dutch courts.

Judge Cockerill held that, under the Civil Jurisdiction and Judgments Act 1982, a foreign ruling on state immunity can be enforced in England if that same decision would have been reached in England.

Russia contends that Judge Cockerill was wrong, and that the English court must consider for itself whether the case falls into an exception for state immunity under the U.K.'s 1978 State Immunity Act.

Russia claims the case does not fall into the exception in Section 9 of the act, which says a state does not have immunity if it has submitted to arbitration.

The awards were set aside by the District Court of The Hague two years after they were issued. That decision was reversed in February 2020 by The Hague Court of Appeal, which ruled that the tribunal had jurisdiction and that its application of the underlying Energy Charter Treaty did not violate Russian law.

The Dutch Supreme Court rejected Russia's jurisdictional challenges in November 2021, sending the case back to reconsider whether Russia can pursue allegations of procedural fraud in the arbitration proceedings.

The shareholders are also fighting sovereign immunity claims from Russia in a parallel legal battle in the U.S.

Russia is represented by Vernon Flynn KC of Brick Court Chambers and Mark Wassouf, Cameron Miles, and Maud Mullan of 3 Verulam Buildings, instructed by Pinna Goldberg.

The investors are Jonathan Crow KC of 4 Stone Buildings and David Peters KC and Naomi Hart of Essex Court Chambers, instructed by Stephenson Harwood LLP.

The case is The Russian Federation v. Hulley Enterprises Ltd. and others, case number CA-2023-002278, in the Court of Appeal.