One of Germany's wealthiest women will seek to enforce a pre-nuptial contract next week in a landmark appeal that, if she is successful, would leave her former investment banker husband with nothing.
Katrin Radmacher, a paper industry heiress worth an estimated £100 million, claims that her estranged husband is seeking to renege on a deal the couple made three months before they married in London in 1998 in which he agreed not to claim against her if they separated.
Although the prenuptial contract would have been fully enforceable in Germany or France, last July Ms Radmacher was ordered by a High Court judge in London to pay her estranged husband, Nicolas Granatino, a lump sum of £5,560,000.
Mrs Justice Baron ruled that it would be "manifestly unfair" to hold Mr Granatino to the contract, which was signed in Germany.
Ms Radmacher is now challenging that award and if she succeeds the ruling could mean that pre-nuptial contracts will become legally enforceable in England. However, most experts expect Ms Radmacher to fail.
Mr Granatino, a French national who worked for JP Morgan, gave up his banking career six years ago to pursue a doctorate in biotechnology at Oxford. He has hired Fiona Shackleton, who advised Sir Paul McCartney is his split with Heather Mills, to represent him.
Julian Lipson, head of family law at Withers, said: "The Court of Appeal will need to weigh up the conundrum between respecting the autonomy of parties to agree a financial settlement at the outset of their marriage, and the need for state interference at the time of divorce to protect the financially weaker party and any children.
"It is a political hot potato for one European member state to be saying that it will not respect a legally binding contract entered into in another, but the English court tends to be paternalistic in protecting divorcing spouses from themselves."