If from the imperfect evidence of foreign law produced before it, or its misapprehension of the effect of that evidence, a mistake is made by an English court, it is much to be lamented, but the tribunal is free from blame.1 The mistake to be lamented presently is the High Court decision in Yukos Capital Sarl v OJSC Rosneft Oil Co2 that a Dutch judgment3 gave rise to an issue estoppel in English proceedings, precluding a party from disputing as a fact the partiality and dependence of the Russian judiciary.4 The decision was a mistake because on a proper construction of Dutch law the significance of the Dutch judgment was—if anything—evidential, not preclusive.5 The outcome is lamentable, because a party was unduly shut out from litigation by the application of English preclusion law to a foreign judgment that was not preclusive in the jurisdiction where it was originally given.6