Permission to appeal has been granted in relation to the judgment of Michael Tappin KC, sitting as a Deputy Judge of the High Court, in Aviator LLC v Spribe OÜ [2026] EWHC 1216 (Ch D). The Judge ruled that, under Rome II, issue estoppel (and indeed all preclusive rules) forms part of the law applicable to the claim. Aviator challenges that ruling on the basis that issue estoppel and wider principles of res judicata are matters for the lex fori.
The issue arose in the context of a wider dispute between Aviator and Spribe concerning the “Aviator” crash game, associated artwork and related copyright and trade mark claims. Aviator contends that earlier Georgian proceedings give rise to issue estoppels which prevent Spribe from re-litigating issues of copyright subsistence, ownership and infringement in the English proceedings. That argument is central not only to Aviator’s UK copyright claim, but also to its claims for copyright infringement in 181 other countries. The Court accepted that the point raised an important question of law with “major consequences for the conduct and shape of the case”.
Aviator’s position was that the effect of the Georgian judgments is governed by English law as the law of the forum, not by the res judicata principles of each country for which copyright protection is claimed. Aviator argued that issue estoppel operates through the English court’s own treatment of the effect of prior adjudications, including the recognition and effect of foreign judgments where relevant.
It was common ground that issue estoppel is substantive in character under English law. However, on Aviator’s analysis, the substantive rights arising from issue estoppel are rights generated by the prior judgment and recognised by the forum; such rights are not the same as, and should not be confused with, the substantive rights that form the subject matter of the underlying non-contractual claim. Once established, issue estoppel operates in the English proceedings by preventing further evidence and argument on issues already conclusively determined. Such effects may be seen as procedural or evidential in character but - on any footing - issue estoppel does not form part of the substantive law of the non-contractual claim in question.
The Judge rejected these arguments. The Judge held that the rules of res judicata are substantive and so fall within the law applicable to a claim under Article 8 (in the case of copyright infringement) and Article 15 of Rome II. The fact that a rule has procedural consequences or forms part of the decision-making process does not mean that it is to be regarded as procedural for the purposes of Rome II.
The Judge also held that English issue estoppel was not an overriding mandatory provision under Article 16 of Rome II, and that applying foreign rules of preclusion would not ordinarily be manifestly incompatible with English public policy under Article 26.
The issue will now proceed to the Court of Appeal.
Philip Roberts KC and
Sam O’Leary acted for the Aviator parties (together with Ed Cronan of 11 South Square), instructed by Allen Overy Shearman Sterling LLP.