Chelsea Football Club owner Roman Abramovich has triumphed over exiled tycoon and Kremlin critic Boris Berezovsky in a UK court battle of the Russian oligarch.

In the biggest ever private case heard by London's High Court, Berezovsky had claimed Abramovich betrayed him and intimidated him into selling shares in the Russian oil company Sibneft for a "mere USD 1.3 B."

He also said Abramovich had broken a promise in a deal involving the Russian aluminum company Rusal. Berezovsky, 66, had claimed USD 5.5 B in damages.

"I dismiss Mr Berezovsky's claim," Judge Elizabeth Gloster told the packed courtroom in London, as cited by RIA Novosti.

"My faith in the British legal system has been destroyed," Berezovsky told journalists.

He said he had not yet decided on an appeal. "That will depend if I have any faith left," he commented.

Berezovsky's lawyer, Andrei Borovkov, told the Rapsi legal news agency that the London High Court had failed to get to grips with the complex reality of Russian business. Borovkov also said the ruling was "unfounded".

Abramovich had denied that Berezovsky was a former business partner and said he was paying him to end an arrangement on "political protection."

A former Kremlin insider during the rule of President Boris Yeltsin, Berezovsky told the court his business relationship with Abramovich, 45, had broken down after he fled Russia after falling out with President Vladimir Putin.

Berezovsky was in court to hear Friday's verdict, but Abramovich was nowhere to be seen.

Both sides had accused each other of dishonesty during the trial, which began last October and ended in January.

In November 2007, a Russian court sentenced Berezovsky to six years in jail in absentia for stealing millions of dollars from the Russian airline carrier Aeroflot in the 1990s.

In June 2009, he was sentenced to a further 13 years in absentia for stealing thousands of cars from carmaker Avtovaz, also in the 1990s. Berezovsky denies the charges.