Tensions between London and Russia escalated further last night when a British diplomat in Moscow was accused of spying.
Chris Bowers, the acting director of UK Trade and Industry, was said by an unnamed source within Russia's intelligence service of being a high-ranking secret service officer.
Mr Bowers, who was named in Russian media reports, was also alleged to have worked undercover as a BBC reporter in Uzbekistan in the 1990s.
A Foreign Office spokeswoman said: "I can confirm that a member of the British staff is suspected of spying by the Russians. However, we do not comment on intelligence matters."
The Interfax news agency reported the Russian intelligence source as saying: "The activities of Christopher Bowers, a counsellor at the British embassy in Russia, and probably, simultaneously a senior officer with British intelligence, are giving rise to questions among Russian intelligence services." It was claimed Mr Bowers engaged in "suspicious" meetings with activists from the north Caucasus, including Chechnya.
The accusations come after talks between Prime Minister Gordon Brown and Russia's President Dmitry Medvedev at the G8 summit in Japan were described as frosty. Relations have worsened since Britain demanded the extradition of Andrei Lugovoy as prime suspect in the murder of Alexander Litvinenko in London in 2006. Tensions have also arisen over the battle for the Anglo-Russian oil company TNK-BP.