Russian tycoon Boris Berezovsky found dead at his UK home 23 March 2013 Last updated at 19:58 The exiled Russian tycoon Boris Berezovsky has been found dead at his home outside London. A police investigation has been launched into the death of the 67-year-old - a wanted man in Russia, and an opponent of President Vladimir Putin. A former Kremlin power-broker whose fortunes declined under Mr Putin, Mr Berezovsky emigrated to the UK in 2000. Thames Valley Police said the death, at a property in Ascot, Berkshire, was being treated as unexplained. The area around the property has been cordoned off to allow the investigation to take place, the force said. The inquiry was at a very early stage and more details will be released when available, it added. Last year, Mr Berezovsky lost a £3bn ($4.7bn) damages claim against Chelsea Football Club owner Roman Abramovich. Diminished wealth Mr Berezovsky claimed he had been intimidated by Mr Abramovich into selling shares in Russian oil giant Sibneft for a "fraction of their true worth." The allegations were completely rejected by the London Commercial Court judge, who called Mr Berozovsky an "inherently unreliable" witness. Fell foul of Kremlin Boris Berezovsky was one of the first Russian oligarchs - that tiny group of tycoons who embraced the end of communism, and used their connections to strike rich almost overnight. While millions of Russians slid into poverty, Berezovsky went into business - he sold cars, bought a stake in Russia's main TV channel, the national airline Aeroflot and an oil company. And as part of "the family" - the tight inner circle around the ailing Russian president Boris Yeltsin - he wielded huge influence in Yeltsin's Russia. But Vladimir Putin was a very different president - a Kremlin leader who would not countenance any businessman telling him how to run Russia. Berezovsky fell foul of the Kremlin and fled to London where he was granted political asylum. From afar he was Vladimir Putin's most vocal critic. On Saturday, President Putin's spokesman said that Mr Berezovsky had asked the president for permission to return home. BBC world affairs reporter Richard Galpin said sources have told him that Mr Berezovsky was depressed after the loss of the court case and was under financial pressure. The tycoon's wealth is thought to have considerably diminished in recent years, leaving him struggling to pay debts in the wake of costly court cases. Mr Berezovsky had made his fortune in the 1990s selling imported Mercedes as well as Russian-made cars. Later owning Sibneft and as primary shareholder in Russia's main television channel, he supported Boris Yeltsin's rise to power. Mr Berezovsky survived numerous assassination attempts, including a bomb that decapitated his chauffeur. During the later years of Yeltsin's presidency, Mr Berezovsky was part of the leader's inner circle as deputy secretary of Russia's security council. "Boris Berezovsky was one of the most powerful men in Russia back in the 1990s," said the BBC's Moscow correspondent, Steve Rosenberg. He rose from being a mathematician, a computer programmer and a used car salesman, to being such an influential figure in Boris Yeltsin's Russia. He then played a role in Mr Putin's rise in the late-1990s, before the new president moved to curb the political ambitions of Russia's oligarchs. Leaving Russia for self-imposed exile in the UK, Mr Berezovsky became one of Mr Putin's fiercest critics. But our correspondent said that on Saturday, a spokesman for Mr Putin said that Mr Berezovsky had sought the president's permission to return to Russia.