Last summer, the Court of Appeal turned English law on its head by enforcing a prenup between a wealthy German heiress and her French ex-husband.
Katrin Radmacher, said to be worth £100 million, and Nicolas Granatino signed the agreement in 1998 in Germany, but the couple spent much of their married life together in London.
Under the agreement, Mr. Granatino agreed not to make any claims on Ms. Radmacher's estate if they split up.
Mr. Granatino reneged on the agreement, however, after the couple divorced in 2006.
Following proceedings in the High Court in 2008, Ms. Radmacher was ordered to pay her ex-husband £5.85 million.
Mrs. Justice Baron said it would be "manifestly unfair" to bind Mr. Granatino to the prenup because he did not receive separate legal advice, Ms. Radmacher did not disclose the extent of her wealth, and English law has never recognised prenups as legally binding.
On appeal last year, however, the award to Mr. Granatino was cut to £1 million as a lump sum in lieu of maintenance. The appeal judges described Mrs. Justice Baron's ruling as "plain wrong" and said English courts should give "decision weight" to prenups.
On Monday, Mr. Granatino appealed to the Supreme Court. He says he faces "financial catastrophe" if the court dismiss his appeal.
He claims he did not know what he was doing when he signed the prenup, as he was "besotted" following a "whirlwind romance". The Court of Appeal decision was both "fundamentally unfair" and "sexist", he adds.
English family lawyers are watching the case with baited breath as it could complete an abrupt volte-face in the courts' attitude towards prenups.
The Guardian quotes Janet Kentridge of Matrix Chambers as saying that English judges have traditionally viewed prenups "without enthusiasm".
"Unfair concessions may be extracted by (generally) wealthier and more powerful men from financially vulnerable women who want to marry them badly enough to sign away the considerable protections of English matrimonial property law," she says.
Or, as Lord Phillips puts it: "You may emotionally be over a barrel when you agree to a prenup."
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