Background
Natalia Potanina was granted unconditional leave to pursue financial relief in England under Part III of the Matrimonial and Family Proceedings Act 1984 following the parties’ Russian divorce. Her sharing and needs claims, listed for final hearing in November 2026, included a claim valued at approximately US$5 billion.
After Vladimir Potanin exhausted his challenge to that leave, he obtained an anti-suit injunction from the Moscow Arbitrazh Court under Russian legislation concerning sanctioned persons. The Russian order required Ms Potanina to terminate the English proceedings and exposed her to potentially substantial penalties for noncompliance. Lieven J subsequently granted Ms Potanina, without notice, an anti-anti-suit injunction, an anti-enforcement injunction and an anti-reliance injunction. The case came before MacDonald J to decide afresh whether those orders should continue.
The Court’s Holding
MacDonald J refused to continue the injunctions. Although satisfied to the required high standard that England was the natural forum for the needs claim and, in the particular circumstances, also for the sharing claim—or alternatively that the English court had a legitimate interest in protecting its proceedings—the judge held that Ms Potanina had not shown to a sufficiently high standard that Mr Potanin’s conduct in seeking and obtaining the Russian order was unconscionable, vexatious or oppressive.
The timing of the Russian application, the husband’s presentation of his access-to-justice arguments, and the potential penalty of up to the value of the wife’s claim did not meet that threshold. The court also considered the overall ends of justice and noted that Ms Potanina had delayed seeking English equitable relief until after fully contesting and losing the Russian proceedings. It likewise refused the requested mandatory notification order and consequential declarations.
The court nevertheless stayed execution for 21 days, leaving Lieven J’s injunctions in force during that period so Ms Potanina could seek permission to appeal to the Court of Appeal.
Key Takeaways
- An applicant seeking continuation of injunctions granted without notice must establish the entitlement to relief afresh at the return hearing.
- A foreign anti-suit order does not by itself justify an English anti-anti-suit injunction; the applicant must satisfy the demanding equitable standard governing interference with a party’s resort to a foreign court.
- Delay and full participation in the foreign proceedings before seeking English equitable relief may weigh against granting an injunction.
Why It Matters
The decision applies anti-suit principles in the unusual setting of Part III financial-remedy proceedings and competing Russian legislation protecting sanctioned persons. It confirms that an English court’s strong interest in preserving proceedings properly before it is not, without more, enough to establish entitlement to anti-anti-suit, anti-enforcement or anti-reliance relief.
The ruling also illustrates the practical collision between cross-border matrimonial claims and sanctions-based jurisdictional rules: the English financial-remedy proceedings remained pending, but the court declined, subject to the temporary appellate stay, to shield the wife from the Russian order’s consequences.