Osborne's friendly oligarch backs Abramovich in his court battle

The battle of the oligarchs entered a further extraordinary chapter yesterday as another of Russia's super-rich gave evidence before the Commercial Court in London.

This time it was the turn of Oleg Deripaska, a billionaire who hit the headlines after he hosted the then shadow Chancellor, George Osborne, and EU trade commissioner, Peter Mandelson, on his yacht off Corfu in 2008.

Said to be even wealthier and more publicity-shy than Roman Abramovich, another power broker and confidant of Vladimir Putin, Mr Deripaska came to the aid of his friend.

Mr Abramovich, 45, is being sued by his former business partner Boris Berezovsky for more than £3bn. Mr Berezovsky is claiming he was forced by Mr Abramovich to sell his share of a hugely profitable oil firm under threats and intimidation.

In testimony that was scathing at times, Mr Deripaska often simply referred to Mr Berezovsky disdainfully as "the person". He described him as a "loner" who failed to honour his debts and commitments, adding it would not have been out of character for him to turn up at a business meeting in the nude.

Too busy with commitments in the United States to come to the UK, Mr Deripaska, 43, was beamed into the London court via video link for an afternoon of evidence.

Mr Berezovsky, 65, is claiming that when Mr Abramovich and Mr Deripaska merged their assets to form the aluminium giant Rusal in 2000, he was a partner. He insists that at a meeting at the Dorchester Hotel in London in March 2000 it was agreed his shares would be held by Mr Abramovich in a trust.

The Chelsea football club owner insists that when he sold a 50 per cent share to Mr Deripaska four years later, it was entirely his own. Mr Berezovsky claims half belonged to him and his business partner Badri Patarkatsishvili.

Yesterday, under questioning from Mr Berezovsky's barrister, Laurence Rabinowitz QC, Mr Deripaska denied that the meeting at the Dorchester had anything to do with Rusal but rather he had merely made a 13-hour round trip to London as a favour to Mr Abramovich, having already done the deal in Russia. He also hoped to ask Mr Berezovsky to repay a debt, he said.

He had, he told the court, loaned Mr Berezovsky £8.5m in 1997 after the other man had begged him: "He was pleading with me because he needed the money for his personal objectives ... it was really touching, quite touching."

"He should have repaid the money a long time prior to that," he said, adding: "I believe Mr Berezovsky has a track record of forgetting about his personal liabilities, commitments and obligations."

Mr Deripaska described the other oligarch as turning up at the Dorchester meeting an hour late in a "ruffled and confused" state wearing a dressing gown over his clothes. When Mr Rabinowitz cast doubt on this, Mr Deripaska said: "He might have turned up in any form, even in the nude. That would have been quite in character."

Clash Of The Financial Titans

Roman Abramovich, 45

Estimated wealth: £8.5bn

Industry: Energy

Born: Saratov, Soviet Union

Residence: London, UK

Yacht: "Eclipse", 536ft long

Interests: Owner of Chelsea FC

Forbes ranking: (2011) #53

Oleg Deripaska, 43

Estimated wealth: £10.6bn

Industry: Metals

Born: Dzerzhinsk, Soviet Union

Residence: Moscow, Russia

Yacht: "Queen K", 238ft long

Interests: Trustee of the Bolshoi Theatre

Forbes ranking: (2011) #36