John Charman, the insurance tycoon who founded Bermuda insurer Axis, has been ordered to pay his ex-wife £48m in what may be Britain's biggest divorce settlement.

The high court ruling is expected to reduce Charman's wealth to around £87m. He has been ordered to pay his estranged wife, Beverley, a £40m lump sum and £8m in assets - 37% of Charman's total assets.

Charman became a well-known figure in the industry when he offered 24-hour war risk insurance during the Gulf War in 1991.

He set up Axis after the 11 September attacks in New York, and built up assets of more than £130m in the insurance market during 29 years of marriage to Beverley. He also became the eighth richest businessman in the City.

The couple split in 2003 and Charman went to live in Bermuda. Beverley issued a petition for divorce and an application for financial settlement in 2004.

Charman described the judgment as "poor and blatantly discriminatory". He said: "The size of the award is grotesque and unfair. I made a fair and open offer to my wife of £20m, which would be impossible for any reasonable person to spend in their lifetime."

He will appeal the ruling.