Berezovsky left court in a President Putin mask

He was held in the UK after an extradition warrant was issued by authorities in Moscow, accusing him of carrying out a huge fraud via his Russian business empire.

The court in London remanded him on bail until 13 May. He also had to surrender his passport.

His life would be in grave danger if he returned to Russia Defence lawyer Alun Jones

Mr Berezovsky, a fierce critic of Russian President Vladimir Putin, left court wearing a mask depicting Mr Putin's face.

The tycoon claims he is the victim of a politically-motivated campaign.

"He lives in fear of assassination by those loyal to the Russian Government. His life would be in grave danger if he returned to Russia," his lawyer, Alun Jones, told the court.

"The history of this case is simple: it's politically motivated. The policy is, 'denounce Berezovsky as a criminal now, we'll find a crime later'.

"It should be noted that the emergence of these allegations... coincided with the rise to power of Mr Putin."

The court ordered that Mr Berezovsky's address should not be made public, to protect him.

Berezovsky says he fears for his life

A request for Mr Berezovsky to be granted political asylum in the UK was turned down last week, the court was told.

Mr Berezovsky is accused of defrauding Russia's south-eastern Samara region in the 1990s while he was head of the Logovaz business empire.

Mr Berezovsky sat in the dock beside another accused man, his business associate Yuli Dubov.

The charges allege that the men defrauded the local government of the Samara region of 60 billion roubles ($1.9 billion) while they were directors of Logovaz from 1994-95.

Mr Dubov's lawyer, Claire Montgomery, said he would be "collateral damage" if both men were returned to Russia.

Out of favour

Mr Berezovsky was closely associated with former Russian President Boris Yeltsin, and was a member of his inner circle of Kremlin advisers.

But his fortunes changed under Mr Putin's government, which Mr Berezovsky claimed was steering Russia back towards authoritarian rule.

Mr Berezovsky has been living in the UK under self-imposed exile.

He has previously told BBC News Online that he would welcome an extradition battle in the UK as a chance to clear his name.