Nicole Kidman and Mariah Carey have them, but Madonna didn't. The "prenup" - a feature of the weddings of the rich and famous - was given legally binding status yesterday by an English appeal court ruling, which will force courts south of the border to respect the agreements.

The Court of Appeal in London ruled that one of Germany's richest women will not have to give her former husband, a former investment banker who is now a researcher, £5.85m of her £100m fortune, after he signed a contract vowing never to make such a claim if they split up.

Paper industry heiress Katrin Radmacher, 39, had argued that Nicolas Granatino's divorce settlement should be governed by the prenuptial agreement signed before their marriage in 1998.

Appeal judge Lord Justice Thorpe said that similar cases before the courts should in future give "due weight" to any contract entered into by both partners before a decision is made on the division of marriage assets, in the most significant decision yet on the issue in the UK.

Mr Granatino, 37, who earns £30,000, will receive £1m as a lump sum in lieu of maintenance with a fund of £2.5m for a house, which will be returned to his former wife when the youngest of their two daughters, six, reaches 22. The heiress had always agreed to a settle his debts of around £700,000.

Lord Justice Thorpe said: "This is not to apply foreign law, nor is it to give effect to a contract foreign to English tradition."

He said it was "a legitimate exercise of the very wide discretion that is conferred on the judges to achieve fairness between the parties" when dividing their assets.

A divorce lawyer said the case would not impact on Scotland's legal system, which already respects the validity of prenuptial agreements, provided they are not fraudulent, signed under duress or without proper legal advice laid down in the benchmark case of two solicitors in Gillon v Gillon in the mid-1990s.

John Fotheringham, of Fyfe Ireland solicitors, which is based in Glasgow and Edinburgh, is one of only eight accredited specialists in child and family law in Scotland. He said: "Prenuptial agreements are regarded in Scottish family law as rather more certain than the much more discretionary system in England.

"Scottish family law can be compared to the beautiful cantilever structure of the Forth Rail Bridge, but the English system is the swirling murky waters of the Firth below. It's not a bad reflection of the position.

"It seems England and Wales is moving very slowly towards the Scottish position."

The marriage of Radmacher and Granatino was said to have broken down after the Frenchman gave up a lucrative job in the markets sector in 2003 to become a moderately paid biotechnology researcher at Oxford University. They divorced in 2006.

Miss Radmacher, 39, said in a statement: "Firstly, I will never regard my marriage as a mistake. I have no regrets as our marriage has given me two wonderful daughters.

"I am delighted that the court accepts that the agreement Nicolas and I entered into as intelligent adults before our marriage should be honoured.

"Ultimately, this case has been about what I regard as a broken promise.

"When we met and married, Nicolas and I were broadly on an equal footing financially. He too is an heir to a multi-million-pound fortune and, when we met, was an investment banker earning up to £330,000 a year.

"The agreement was at my father's insistence as he wanted to protect my inheritance - this is perfectly normal in our countries of origin, France and Germany. My father taught me the value of hard work and family values. Like all wealthy parents, he feared gold-diggers."

Her solicitor, Ayesha Vardag, said: "For 160 years prenuptial contracts were said to be void for public policy reasons. They were put in the same category as contracts to kill your hated spouse.

"From today, grown-ups can agree in the best of times what will happen in the worst of times."

Miss Radmacher challenged the earlier Family Division ruling by Mrs Justice Baron that it would be "manifestly unfair" to hold Mr Granatino to the pre-nuptial contract, which was signed in Germany before the couple married in London in 1998.

Although the judge recognised that the pre-nuptial agreement would have been fully enforceable in Germany or France, she ruled that they have never been legally binding in England.

Lord Justice Thorpe said he believed it had become "increasingly unrealistic" to regard such contracts as void.

He said: "It reflects the laws and morals of earlier generations. It does not sufficiently recognise the rights of autonomous adults to govern their future financial relationship by agreement in an age when marriage is not generally regarded as a sacrament and divorce is a statistical commonplace."

Mr Granatino is now set to take the case to the House of Lords. "It will be interesting to see if they bring in a Scottish law lord, such as Lord Hope, who has experience of the family law position here, for that," said Mr Fotheringham.