Exiled Russian businessman Boris Berezovsky said on Wednesday British police warned him last month of a plot to kill him and he fled the country, escaping a threat he said bore the hallmarks of Russia's security service.

Berezovsky, a fierce critic of Russian President Vladimir Putin, whom he has blamed for the murder of former KGB agent Alexander Litvinenko, said he left Britain on June 16 for a week, until police advised him the plot had been foiled.

Police confirmed they arrested a man on June 21 in connection with a plot to kill Berezovsky but released him two days later without charge, handing him to immigration officials.

Berezovsky, 61, said the man was deported to Russia, but that was not confirmed by police or interior ministry officials.

"I received a call from Scotland Yard police a month ago informing me that there was a plot to kill me and telling me to leave the country," Berezovsky, who was granted political asylum in Britain in 2003, told a news conference, at which several personal bodyguards and a unit of British police were on hand.

"The same people who were behind the Litvinenko plot, they want to kill me."

He said his news conference had no link to the deepening dispute between Britain and Russia, in which Britain on Monday expelled four Russian diplomats because of Moscow's failure to hand over Britain's chief suspect in the Litvinenko murder.

British prosecutors suspect that Andrei Lugovoy, a former KGB agent, poisoned Litvinenko, also an ex-KGB agent, with the rare radioactive isotope polonium 210 in London last year, and want him extradited to face justice.

Moscow is expected to respond to the diplomatic expulsions within the next 48 hours.

Russia's ambassador to London said his government was not behind any alleged plot. A spokesman for Prime Minister Gordon Brown said the government would not comment on speculation about security matters.

PUTIN CRITIC

Berezovsky, who says he wants a "bloodless revolution" in Russia and the end of Putin's rule, said on Wednesday he had spent $300-400 million (146-195 million pounds) funding opposition groups in his former homeland since he went into exile in 2001.

Britain has refused to extradite Berezovsky to Moscow where he is being tried in absentia for theft. He said he had had many death threats in recent years and accused Russia's security service of being behind them.

Asked why he thought the Russians would want to kill him, Berezovsky, a colourful character who speaks broken English, said it was because he was a key witness to Litvinenko's death and the main funder of Russian opposition to Putin.

Russia's ambassador to London, Yury Viktorovich Fedotov, dismissed any suggestion the Russian government might have been behind the plot. "That is excluded," he told BBC radio.

Asked what he thought of Berezovsky's comments he said: "That is quite strange information and I have nothing that could confirm it." He accused Berezovsky of links to "money laundering, corruption, and organised crime".

Lugovoy, a former KGB security agent, has repeatedly said he is innocent of murder charges. He says Litvinenko was probably killed by fellow Russian emigres or British security services.

(Published by Reuters, July 18, 2007)