Shan Lambert, 50, claimed at the Court of Appeal that she made an equal contribution to her former husband's business and was therefore entitled to half its £20m valuation.

She was married for 23 years to the founder of the Adscene newspaper chain, 58-year-old Harry Lambert, who contested her claim.

Lord Justice Thorpe, who, along with Lord Justice May and Mr Justice Bodey heard the case last month, said the decision recognised the value of Mrs Lambert's role in the family.

'Homemakers' valued

Last year, Mrs Lambert was awarded the marital home - Ringleton Manor, near Sandwich, Kent, worth £1.4m - together with the accompanying Ringleton Lodge, worth £250,000.

She was also allowed to keep assets worth £2.8m and was given a lump sum of £3,152,732.

On Thursday, the cash figure was increased to ensure Mrs Lambert's settlement amounted to 50% of her husband's assets.

Announcing the decision, Lord Justice Thorpe said: "There must be an end to the sterile assertion that the breadwinner's contribution weighs heavier than the homemaker's."

'Laws needed'

Martin Pointer QC, representing her former husband, had told the appeal judges that she had "pitched her case very high indeed".

He said if she used her initial award as an investment it would give her an annual income in excess of £250,000.

Nicholas Mostyn QC, representing Mrs Lambert, told the judges the laws of this country should reflect the fact that marriage is a true and equal personal partnership.

He said: "As there is no prospect of legislation to put this in practice, it is for the courts to decide, case by case, precisely what the principles are."