A former Russian spy accused of murdering the defector Alexander Litvinenko has sensationally claimed MI6 was involved in his murder.
Andrei Lugovoy said he had evidence the British security services had a hand in the murder of ex-spy Litvinenko, who died last November after being poisoned with polonium-210.
British intelligence agents also tried to recruit him to get information about President Putin - and both Litvinenko and Russian tycoon Boris Berezovsky were on its pay, he claimed.
But the allegations were immediately dismissed by Mr Berezovsky, who described them as further proof Lugovoy was acting according to Kremlin instructions.
Alex Goldfarb, a close friend of Litvinenko, agreed, saying Lugovoy's statement illustrated once again that the Russian government was behind the spy's death.
The startling allegations made at a press conference in Russia are the latest twist in an investigation that has been so full of mystery and political intrigue that it would be more fitting for the plot of a James Bond film.
Lugovoy claimed: "Even if (British special services) hadn't done it (killed Litvinenko) itself, it was done under its control or connivance."
In the translation by Russia Today television channel, he later added British agents had "asked me to collect compromising information on President Putin".
When asked if he could back up the claims, Lugovoy said: "I have evidence", but went no further.
Papers calling for his extradition were delivered to Russia on Monday after the Crown Prosecution Service's announcement that Lugovoy was being charged with Litvinenko's murder. The Russians have already said he will not be extradited.