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.
A South Central Ambulance Service spokeswoman said it had been called to the property at 15:18 GMT.
“We sent a number of ambulance officers and an ambulance to the address. The 67-year-old male was confirmed deceased at the scene,” she said.
Last year, Mr Berezovsky lost a £3bn ($4.7bn) damages claim against Chelsea Football Club owner Roman Abramovich.
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 Berezovsky an “inherently unreliable” witness.