A city tycoon has failed in his attempt to reduce the divorce settlement agreed with his wife in 2008.

Investor Brian Myerson and his wife Ingrid divorced at the peak of the recent boom. The settlement involved him giving his ex-wife a lump sum of &pound9.5 million and a property in South Africa worth &pound1.5 million. Although he has mortgages and other liabilities of &pound2.5 million, this still left Mr Myerson with a considerable fortune, his investment company being then valued at more than &pound15 million. At the time, the settlement left Mr Myerson with 57 per cent of the couple’s total assets.

Then came the credit crunch. Mr Myerson’s shareholding in his company is now valued at less than &pound2 million, meaning he has a negative net worth in the region of &pound500,000. &pound2.5 million of the original sum due to Mrs Myerson is still unpaid.

Mr Myerson went to the Court of Appeal in a bid to have the settlement overturned but the Court rejected his argument. In its view, the “natural process of price fluctuation, however dramatic”, did not satisfy the legal test for a change in a settlement.

The ruling will come as a blow to many wealthy divorcees who were hoping to renegotiate their settlements. However, Mr Myerson is reported to be intending to appeal to the House of Lords.