ALL couples were advised last night to sign prenuptial agreements before getting married after a landmark ruling that gives wives much bigger divorce settlements.

Family lawyers said that wealthy young men and women would be better off not marrying at all after Britain’s highest court ruled that a wife may be entitled to half the assets created during even a short marriage.

In the most important judgment on divorce for more than 20 years the law lords ruled that women who sacrifice careers to bring up children and look after the home should be compensated and may claim a share of their husband’s future income.

Ruling on two test cases they said that Melissa Miller, 36, could keep the £5 million that she was awarded from the £17.5 million fortune of her husband Alan, 42, a City fund manager; and that Julia McFarlane, 46, was entitled to £250,000 a year from her husband Kenneth, 46, a tax specialist, for as long as she needs it.

Emma Hatley, a partner at Withers, which advised Mrs Miller, said: “The ruling will serve as a deterrent to marriage. But prenuptial agreements will provide a good degree of protection — and I predict it will not be long before they are made binding. It’s not if, it’s when.”

Jeremy Levison, Mr McFarlane’s lawyer, said he would advise wealthy young men not to marry. “It will have the effect of discouraging successful guys from getting married at all. You get these young women, in their thirties, the body clock starts ticking, and they are looking for someone to have their babies — then the marriage breaks up after a short while. I am already advising these kinds of men that they would be better off not marrying.”

Failing that, he would urge prenuptial agreements. “My advice is: 1, don’t marry; 2, if you do make sure your other half is as wealthy as you are and 3, do a prenuptial agreement and keep your fingers crossed.”

The judgment lays down guidelines on how to split assets between partners in multimillion-pound settlements, such as that looming for Heather Mills and Sir Paul McCartney.

But it also has an impact on ordinary divorces where husbands are high-earners and where wives can now hope for higher settlements.

Many welcomed the ruling as a ground-breaking victory for wives that recognised their contribution as equal partners in a marriage and a new definition of “fairness”.

Lawyers also anticipated that the guidance from the law lords would prompt more out-of-court settlements and cut divorce costs. They endorsed the “closing of the lid” on adultery, or conduct, as a factor in determining a divorce settlement.

Andrew Greensmith, chairman of Resolution, the association of family solicitors, said that the ruling was the most significant for 20 to 30 years.

“The Matrimonial Causes Act 1973, set out the factors courts muct take into account when deciding finances on divorce. It was amended in 1981 to say that courts no longer had to put the parties — usually the wife — back in the position she would have been before the marriage,” he said.

“Until now the courts have never defined fairness. Baroness Hale has now said there should be three elements: needs, contribution and compensation.”

Outside court Mrs McFarlane’s lawyer James Pirrie said: “Until today maintenance for a stay-at-home mum was based purely on her living costs. Now judges must consider contribution and compensation for people like Julia. The judgment recognises her sacrifice.”

Explore Law

• Columnists

• Law Panel

• Law Reports

• Student Law

Times Recommends

• Linklaters trounces rivals as UK's biggest firm
• Clifford Chance profits plunge 37 per cent
• Casual drinkers hit by spread of 'dry' zones