Russian oligarch Boris Berezovsky has lost his High Court battle with Chelsea Football Club owner Roman Abramovich.
Mr Berezovsky, 66, was seeking more than £3 billion damages after accusing the 45-year-old Russian billionaire businessman of blackmail, breach of trust and breach of contract.
Mr Abramovich denied the allegations and denied that Mr Berezovsky was entitled to damages.
Mrs Justice Gloster ruled in Mr Abramovich's favour today after a trial in London which started in October 2011 and ended in January this year.
The legal fight centred on deals done in Russia following the break-up of the Soviet Union two decades ago.
Mr Berezovsky - who attended court today for the ruling - told the trial that Mr Abramovich had "intimidated" him into selling shares in a Russian oil company at a fraction of their value.
He also told the judge that Mr Abramovich had broken a promise made during a deal relating to a Russian aluminium company.
Mr Abramovich disputed the claims.
Both men "rose to enormous wealth and influence" in Russia in the 1990s as state-owned firms were privatised in the wake of the collapse of communism, the court heard.
But Mr Berezovsky fled Russia, never to return, in late 2000, after falling out with President Vladimir Putin.
He travelled initially to France, then settled in England.
He claimed that he had been betrayed by his former friend and business partner.
Mr Abramovich said Mr Berezovsky's claims were "wholly without merit".
During the trial, Laurence Rabinowitz QC, for Mr Berezovsky, said both men had worked together to acquire Russian oil company Sibneft - and became friends.
Mr Berezovsky claimed that in 1995 he, a colleague and Mr Abramovich agreed to "work together" to bring Sibneft under their control.
They had persuaded then Russian president Boris Yeltsin to "bring about the privatisation of Sibneft and its disposal into their hands", said Mr Rabinowitz.
But Mr Abramovich had intimidated Mr Berezovsky and his colleague into selling their ownership interest in Sibneft at a "massive undervalue" and put Mr Berezovsky "in fear for the life of his friend and the risk that his property might be expropriated", said the QC.
Jonathan Sumption QC, for Mr Abramovich, said Mr Berezovsky was paid millions of pounds by businesses controlled by Mr Abramovich for his services as a "political godfather".
But Mr Sumption said Mr Berezovsky had not "contributed a single cent" to acquiring or building up Sibneft, nor made any managerial contribution.
He said Mr Berezovsky's contribution had been "important, indeed... indispensable" but "almost entirely political".