One of Germany's richest women, Katrin Radmacher, is to use the British courts in an attempt to enforce a prenuptial agreement which would leave her ex-husband without a penny of her £100 million fortune.
In a landmark case, Miss Radmacher, a paper industry heiress, will argue that Nicolas Granatino is bound by an agreement he signed before their marriage in 1998 in which both parties agreed not to make any claim on the other if they divorced.
If she is successful, it could result in prenuptial contracts becoming legally binding under English law for the first time.
Mr Granatino, 38, who gave up his job as an investment banker to become a £30,000 a year researcher at Oxford University, has already been awarded a £5.6 million lump sum following a High Court hearing last July.
On that occasion Mrs Justice Baron ruled that it would be "manifestly unfair" to hold Mr Granatino to the contract, which was signed in Germany before the couple married in London.
Miss Radmacher, 39, will take the case to the Court of Appeal next week, but her legal team will face a formidable barrier in the form of Fiona Shackleton and Nicholas Mostyn QC, the lawyers who represented Sir Paul McCartney in his divorce from Heather Mills and who have been hired by French-born Mr Granatino.
The couple met in Tramp, the members-only nightclub in Mayfair, when Mr Granatino was working as a £320,000 a year merchant banker for JP Morgan, and his wife was running a clothes shop in Knightsbridge with her sister. The couple went on to have two daughters now aged nine and six.
Problems began in 2003 when Mr Granatino decided on a change of career and took up a lowly-paid post as a biotechnology researcher at Oxford, and the couple divorced in 2006.
At the previous hearing, Mrs Justice Baron heard that the husband had "virtually no assets" whilst his ex-wife had £54m in liquid assets and another £52m in capital assets, giving her an annual income of £2m.
Although the judge recognised that the prenuptial agreement would have been fully enforceable in Germany or France, they have never been legally binding here, and she said that the arrival of the couple's children had "so changed the landscape" that it should be set aside, and awarded Mr Granatino £5,560,000.
She 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.
Miss Radmacher, meanwhile, 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".
Miss Radmacher was granted leave to appeal after two judges ruled that she had an "arguable case" that her husband should only be entitled to maintenance payments to cover the cost of looking after the couple's daughters, who spend a third of their time with their father and the remainder with their mother in Düsseldorf.
The outcome of the case will be keenly anticipated by divorce lawyers in London, seen as the divorce capital of the world because of the number of wealthy foreign couples who choose to make their homes here.
English courts tend to protect the weaker financial party in divorce cases, and most experts expect Miss Radmacher to fail.
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."