Heiress's case to decide status of pre-nup deals

A German heiress will go to court today to try to stop her former husband from making claims on her £100m fortune in a landmark case which will decide the status of pre-nuptial agreements.

The highest court in the country will rule on whether it is fair to allow Katrin Radmacher, 39, to hold Nicolas Granatino, 37, to the strict terms of a contract which restricts his size of the divorce spoils.

At the time of their marriage in 1998, Mr Granatino was working for JP Morgan and earning as much as £325,000 a year. But when the couple separated in 2006 Mr Granatino had left to work as research scientist at Oxford University. Ms Radmacher accused her husband of deliberately delaying his doctorate to "maximise his claim" and said that if he "wishes to be an academic he must live as such".

The couple met in Tramp, the members-only nightclub in Mayfair, when she was running a clothes shop in Knightsbridge with her sister. They married in London after signing a pre-nuptial contract in Germany and have two daughters.

At the first hearing in the High Court, Mrs Justice Baron heard that Mr Granatino had "virtually no assets" whilst his ex-wife's interests in the paper industry gave her £54m in liquid assets and £52m in capital assets, providing her with an annual income of £2m.

Although the judge recognised that the pre-nuptial agreement would have been fully enforceable in Germany or France, they have never been legally binding here, and she said the arrival of the couple's children had "so changed the landscape" that it should be set aside, and she awarded Mr Granatino £5,560,000. Mrs Justice Baron also noted that the husband had not received independent legal advice before signing the contract and his wife had not disclosed the full extent of her assets at the time.

But the Court of Appeal reinstated the terms of the pre-nuptial agreement – that in the event of divorce neither party would make a claim on the other's money – reducing his share of the divorce to just £1m.

Family law experts hope the judges of the Supreme Court will now clarify the law. The Law Commission, which advises the Government on legal reforms, is to publish a draft Bill on this issue in 2012.

Michael Gouriet, partner in the family law team at Withers law firm in London said: "People often ask whether pre-nups are worth the paper they are written on. The Court of Appeal has demonstrated that they are, but it will be interesting to see whether, in the absence of legislative reform, the Supreme Court considers that the Court of Appeal have pushed the boundaries of discretion too far.

"It is a political hot potato for one European member state to be saying it will not respect a legally binding contract entered into in another, but the English courts tend to be paternalistic in protecting divorcing spouses from themselves."

A fair share? When wealthy couples split

*Heather Mills had offered to sign a pre-nuptial agreement but Paul McCartney had refused because he did not believe it would be necessary. He considered neither financial issues nor the 26-year age gap mattered much. She got £24m.

*Michael Douglas was one celebrity who did have a detailed pre-nuptial agreement when he married Catherine Zeta Jones. He learnt the hard way when he had to pay his first wife a settlement of £20m. Zeta Jones would be paid £1.4m of Douglas's fortune for every year of their marriage.

*Steven Spielberg met Amy Irving when she auditioned for Close Encounters of the Third Kind in 1977. When they split in 1989, Irving contested their pre-nuptial agreement, reportedly scribbled on a napkin, because she did not have a lawyer. She was awarded £50m, about half his fortune at the time.