Boris Berezovsky fled Britain three weeks ago on the advice of Scotland Yard, amid reports that he was the target of an assassination attempt by a suspected Russian hitman.

The exiled tycoon and fierce critic of President Putin of Russia told The Times last night that he had been warned that it was not safe for him to remain in London, where he had been living since being granted asylum in Britain.

“I was informed by Scotland Yard that my life was in danger and they recommended that I leave the country,” he said. “I left three weeks ago but have now returned.”

Mr Berezovsky, a billionaire businessman who has an office in Mayfair and lives at a heavily guarded mansion in Surrey, never moves without a phalanx of bodyguards. He has been the subject of assassination attempts in Russia but this is the first time that he has been targeted in London.

Reports last night claimed that an assassin was captured at the Hilton Hotel in Park Lane, West London, moments before he planned to kill Mr Berezovsky, whose offices are a short distance away. Scotland Yard said last night that it was not prepared to discuss the matter.

The revelation could help to explain why the new Government of Gordon Brown decided to take such tough action against the Kremlin this week. On Monday David Miliband, the Foreign Secretary, ordered four Russian diplomats, believed to be members of the Russian security services, to leave Britain within ten days. He also announced measures to tighten visas for Russian officials visiting Britain.

The reason given for the action was Russia’s failure to extradite Andrei Lugovoy, a former Russian intelligence officer, who has been named as the prime suspect in the murder of Alexander Litvinenko. Mr Litvinenko, an associate of Mr Berezovsky’s, died an agonising death in November last year when he was poisoned with the radioactive isotope polonium-210. Detectives believe that Mr Lugovoy administered the poison in a pot of tea he served Mr Litvinenko when they met at the Millennium Hotel in Mayfair on November 1.

At the time, Russian opposition figures in London suspected that the murder was intended to send a message to Mr Berezovsky, who has openly called for the removal of President Putin and his regime by peaceful means, or by force if necessary.

The former Kremlin aide and Russian oligarch made billions of pounds in the 1990s when he ran an airline, a car dealership and Russia’s main television channel. He briefly served as a Kremlin aide during the presidency of Boris Yeltsin.

But he fell out with Mr Putin and fled the country. The Kremlin has sought his extradition back to Russia to face various criminal charges but he was granted asylum to remain in Britain by David Blunkett, the former Home Secretary.

Since arriving in Britain, Mr Berezovsky has been a political irritant to the Kremlin. He has used his wealth and political contacts to fund the opposition against Mr Putin, who is due to step down as head of state after next year’s presidential elections. In the politically charged atmosphere ahead of the changeover of power there are fears that figures in the Kremlin will seek to silence or eliminate any opposition figures threatening the existing leadership.

Mr Berezovsky said last night he was confident he was safe in Britain under the protection of the police. Appearing on Newsnight on BBC One, he said that he was in no doubt that the threats to his life came from the Russian Government. He said he was “100 per cent sure” that Mr Putin was behind Mr Litvinenko’s murder.

Relations between London and Moscow are likely to be tense for some time. Yesterday Yuri Fedotov, the Russian Ambassador to London, gave a warning that Moscow would retaliate against the expulsion of the four diplomats from his embassy. While tit-for-tat expulsions would not seriously damage bilateral relations, Britain is concerned the Kremlin could harm the lucrative British commercial interests in Russia.

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