Potanin, one of Russia's richest men and the CEO of metals producer Norilsk Nickel, had asked the United Kingdom's Supreme Court to throw out Natalia Potanina's attempt to bring a mammoth divorce claim in the English courts.

Potanina wants to bring a claim for financial relief following their divorce, capped at 50% of the value of her ex-husband's ultimate beneficial interest in shares in Nornickel, dividends paid since 2014 and a Russian property.

But Potanin's lawyers said the Supreme Court should throw out her claim as the couple had no connection with Britain during their marriage and Potanina had already received tens of millions of dollars following Russian divorce litigation.

The Supreme Court ruled by a three-to-two majority that a lower court applied the wrong legal test when granting Potanina permission to bring a financial claim in Britain, which was previously valued by her lawyers at around $9 billion.

But the case was sent back to the Court of Appeal to decide issues that were not resolved in 2021 when Potanina's case was given the go-ahead.

(Reporting by Sam Tobin; editing by William James)