Roman Abramovich (L) has won his legal battle against Boris Berezovsky (Reuters)
Roman Abramovich (L) has won his legal battle against Boris Berezovsky (Reuters)

Russian tycoon Boris Berezovsky has lost his High Court battle with Chelsea Football Club owner Roman Abramovich in the biggest private litigation case in British legal history.

Berezovsky, 66, was seeking around £3.8bn from Abramovich, claiming he "betrayed" and "intimidated" him into selling shares in the Russian oil company Sibneft for a "mere $1.3bn" (£820m).

Berezovsky also accused Abramovich, 45, of blackmail, breach of trust, and breach of contract after reneging on a promise in a deal involving Russian aluminium company RUSAL.

Abramovich denied all accusations and was not at the court to hear the verdict.

Judge Elizabeth Gloster said at the ruling: "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 added: "At times the evidence which he gave was deliberately dishonest; sometimes he was clearly making his evidence up as he went along in response to the perceived difficulty in answering the questions in a manner consistent with his case.

"At other times, I gained the impression that he was not necessarily being deliberately dishonest, but had deluded himself into believing his own version of events.

The court heard how the two billionaires became friends after working together to acquire Sibneft, and then agreed to work with another colleague to bring the company under control.

But Berezovsky claimed the Chelsea owner "intimidated" him and their colleague into selling their ownership interest in Sibneft at a "massive undervalue".

Abramovich, the world's 68th richest man, said Berezovsky was paid millions of pounds for his services as a "political godfather" but was not a business partner of his.

Justice Gloster ruled in Abramovich's favour after a three-month trial, adding she found him "to be a truthful, and on the whole reliable, witness".

Berezovsky has spent a reported £100m fighting the case, which has involved an army of lawyers.

Berezovsky fled from Russia to France in October 2000, following a dispute with Vladimir Putin, after he was elected President of Russia in March 2000.

Upon his arrival in court Berezovsky told reporters: "I believe in the system."

Berezovsky amassed his wealth during Russia's privatisation of state assets in the early 1990s.

In return for backing former Russian President Boris Yeltsin, he gained powerful political connections and access to valuable assets at very low prices.