Chelsea FC owner Roman Abramovich has won his legal battle against exiled Russian oligarch Boris Berezovsky.
Mr Berezovsky, 65, said Mr Abramovich, 45, had intimidated him into selling shares in Russian oil giant Sibneft. He was claiming £3bn ($4.7bn) in damages.
But the London Commercial Court judge said Mr Berozovsky had been an “inherently unreliable” witness.
Mr Berezovsky said he was “shocked” at Mrs Justice Gloster’s decision and that she had rewritten Russian history.
The BBC estimates the total legal costs in the case are up to £100m.
In her ruling the judge said: “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 she dismissed Mr Berezovsky’s claims in relation to Sibneft – and a claim Mr Abramovich had broken a promise over a deal involving Russian aluminium company RusAl – “in their entirety”.
She also said she found Mr Abramovich “to be a truthful, and on the whole reliable, witness”.
Mr Berezovsky, who had told reporters before the verdict that: “I believe in the system”, afterwards said : “I am absolutely amazed by what’s happened today… particularly because Lady Gloster took the responsibility to rewrite Russian history.”
Asked if he felt Russia’s President Vladimir Putin would be happy with the ruling, he replied: “Sometimes I have the impression that Putin himself wrote this judgment.”
He said he did not regret bringing the case against Mr Abramovich and did not know if he would appeal, adding: “I was absolutely shocked… but life is life.”
The BBC’s Moscow correspondent Daniel Sandford said there had been a lot of interest in the case in Russia as it shed light on the controversial sale of Russia’s mineral wealth by the state to a small group of oligarchs in the early 1990s.
Mr Abramovich was not in court for the ruling and is thought to be in Monte Carlo for Chelsea’s Super Cup Final on Friday night.
But a statement issued on his behalf said: “There were many serious allegations made against Mr Abramovich by Mr Berezovsky, including attacks on Mr Abramovich’s honesty and integrity.
“We are pleased that the judge has firmly rejected all such allegations and has described Mr Abramovich as a truthful and frank witness who showed a responsible and honest approach when giving evidence in this case.”
When he gave evidence, Mr Abramovich had said Mr Berezovsky was paid millions of pounds for his services as a “political godfather” but was not a business partner.
The court heard Mr Berezovsky “fled Russia, never to return” in 2000, after falling out with President Vladimir Putin.
Both men have homes in London, with Mr Abramovich owning a property in Knightsbridge as well as a 400-acre estate in Fyning, West Sussex.
On his arrival in court on Friday Mr Berezovsky, who now faces a huge legal bill, had told reporters: “I believe in the system.”
During the three-month trial, the court heard details of the lifestyles of Russia’s super-rich oligarchs.
Mr Berezovsky claimed Mr Abramovich was a “gangster” while Mr Abramovich responded by saying there were times when Mr Berezovsky was “something of a megalomaniac”.
The hearing was told Mr Abramovich bought a businessman a plane to say thank you after one deal.
Mr Berezovsky told the court he was born in Moscow, studied mechanics and mathematics and worked as a designer for Russian state car maker AvtoVAZ in the 1970s, before going into business in the 1980s.
In the 1990s, following the collapse of communism, Mr Berezovsky embarked on a political career and Mr Abramovich’s lawyers claimed he was a “power broker” and a “highly controversial figure”.
The hearing was told Mr Berezovsky’s expenses – including “palaces in France”, “private aircraft”, “valuable paintings” and “jewellery for his girlfriend” – were paid for by Mr Abramovich.
Danny Jowell QC, for Mr Abramovich, told Friday’s hearing they were concerned Mr Berezovsky may have been “disposing of assets in recent months”.