Tycoon Boris Berezovsky loses key witness in case against Roman Abramovich

As murmurings grow louder that Boris Berezovsky might not be quite so rich as he once was, it seems his friends are deserting him too.

Mikhail Chernoy, the Uzbekistan-born Israeli aluminium magnate, will no longer be appearing as a witness for Mr Berezovsky in his £3.5bn claim against Chelsea owner Roman Abramovich, 45.

Mr Chernoy, who is prevented from travelling to the UK after Interpol issued a warrant for his arrest over money laundering charges in Spain, was expected to give evidence via video link from his home in Israel later this week, but London's Commercial Court heard yesterday the appearance was cancelled.

Mr Berezovsky, 65, is seeking damages from Mr Abramovich, claiming he intimidated him into selling his stakes in valuable oil, aluminium and media businesses. He previously admitted Mr Chernoy had given him $50m to "help me with my life", but has disputed suggestions Mr Chernoy stood to gain financially should the action be successful. He has admitted such arrangements exist with other parties.

The court heard Mr Chernoy does not wish to appear as it may compromise his own $2bn lawsuit against Russian oligarch Oleg Deripaska, due to be heard in London next April. As things currently stand, Mr Chernoy will appear via video link in that trial.

Mr Deripaska, who came to the British public's attention three years ago when details emerged of a meeting on his yacht between George Osborne, Peter Mandelson and the financier Nathaniel Rothschild, may yet appear as a witness for Mr Abramovich.

Later this week or next, the court will hear from David Reuben, one of the two Reuben Brothers, who are Britain's second wealthiest people, with an estimated fortune of £5.5bn. It was their metals business that was the chief exporter of Russia's aluminium, making them significant players in the "aluminium wars" of the 1990s, which claimed several lives in violence between criminal gangs for control of the commodity.

The courtroom is expected to be filled next Monday, when Mr Abramovich, who has sat silently through the first three weeks of the trial, gives evidence.