Russian oligarch Boris Berezovsky lost his long-running legal battle with fellow tycoon Roman Abramovich in London's High Court on Friday and was roundly criticised by the trial judge.
Berezovsky, 66, was seeking more than £3 billion ($4.75 billion, 3.8 billion euros) in damages after accusing the 45-year-old owner of Chelsea football club of blackmail, breach of trust and breach of contract.
But Judge Elizabeth Gloster ruled in Abramovich's favour and described Berezovsky as an "unimpressive and inherently unreliable witness" after a trial which started in October last year and ended in January.
Berezovsky claimed Abramovich "betrayed" him and "intimidated" him into selling shares in the Russian oil company Sibneft for a "mere 1.3 billion dollars". Abramovich firmly denied the allegations.
The judge said the case boiled down to "whether to believe Berezovsky or Abramovich".
Because the claims "depended so very heavily on the oral evidence of Mr Berezovsky, the court needed to have a high degree of confidence in the quality of his evidence", she said.
The judge added: "That meant confidence not only in his ability to recollect things accurately, but also in his objectivity and truthfulness as a witness."
In a lengthy analysis, she added: "On my analysis of the entirety of the evidence, I found Mr Berezovsky an unimpressive, and inherently unreliable, witness, who regarded truth as a transitory, flexible concept, which could be moulded to suit his current purposes."
She said that "on occasions he tried to avoid answering questions by making long and irrelevant speeches, or by professing to have forgotten facts which he had been happy to record in his pleadings or witness statements".
Abramovich and Berezovsky have spent a reported 100 million pounds fighting the case, which has involved an army of lawyers.
The case shone on a spotlight on the lavish lifestyles of the oligarchs, and the political influence that Berezovsky wielded when Boris Yeltsin was Russian president.
Abramovich told the court that Berezovsky was paid millions of pounds for his services as a "political godfather" but was not a business partner of his.
Berezovsky fled Russia in 2000 after he fell out with Vladimir Putin during his first term as president.
He enjoyed the title of being the power behind the Kremlin throne in the 1990s when Yeltsin, in failing health, was forced to frequently remove himself from daily affairs and hand key decisions to advisers.
Berezosky once claimed credit for the idea of picking Putin as Yeltsin's chosen successor before admitting that the plan backfired when the new Russian surrounded himself with more trusted agents instead.
The so-called Kremlin "family" that clustered around Yeltsin at the time included Berezovsky and the president's daughter as well as several other tycoons who suffered badly once Putin rose to power.