Tycoon Pierre Lagrange comes out – to face UK's most expensive divorce payout

Pierre Lagrange, right, with his new partner, the fashion designer Roubi L'Roubi (BILLY FARRELL/REX FEATURES)

A top hedge fund manager is facing one of the most expensive divorce settlement in British legal history after telling his wife he is gay.

Pierre Lagrange, who is said to be worth at least £300m through running the firm GLG Partners, has sold his opulent London home on the road known as "billionaire's row" in anticipation that half his wealth could be claimed by his wife, Catherine.

A spokesman for GLG confirmed that the couple split last year after the Belgian came out to his family and friends, and he has since started a relationship with Roubi L'Roubi, a Mayfair fashion designer.

The Chelsea FC owner Roman Abramovich has paid £90m for Mr Lagrange's 15-bedroom house in Kensington Palace Gardens, where his new neighbours will include the richest man in Britain, Lakshmi Mittal, and the oil magnate Len Blavatnik. But it is entirely possible Mr Lagrange will have to find another £60m to meet the financial demands of his split.

The current record is around £100m, granted to the wife of the Russian oligarch Boris Berezovsky. The leading divorce lawyer Ayesha Vardag said that the increasing frequency of such sums is raising eyebrows.

"There is a general concern that awards are too high and that the principle that has been in place since 2000 – of generally sharing equally no matter who earned it – is being somewhat stretched in the light of the huge awards that are coming through.

"The courts have said that these awards are bigger than anyone expected they would be. It would invite a re-evaluation of the straight forward 50/50 approach to marital assets."

Mr Lagrange can at least take some heart that a £150m payout would not be the biggest amount of money he has had to write off, having lost an estimated £265m during the credit crunch.

That did not stop GLG, a company that also gained from the financial crisis by short-selling Bradford and Bingley shares before the bank collapsed, being bought by a rival for $1.6bn three years later – a sale that saw the 49-year-old former Goldman Sachs man claw back much of his former wealth.

His wife is a leading donor to the Conservatives, having given the party £100,000 in the run-up to last year's general election, on top of a previous £50,000 gift. As well as giving money to cultural organisations, Mr Lagrange has also found the arts to be a profitable sector having invested in the films Avatar and Kick-Ass.