Russia yesterday unveiled a memorial plaque to British double agent Kim Philby at the headquarters of the Foreign Intelligence Service in central Moscow, a spokesman for the agency said.

The head of the Foreign Intelligence Service (SVR), Mikhail Fradkov, unveiled the plaque on the wall of the agency’s press office at a ceremony attended by his widow Rufina Pukhova-Philby, spokes­man Sergei Ivanov said.

In a photograph of the ceremony sent by the SVR, Mrs Pukhova-Philby, wearing a fur-trimmed coat and tinted glasses, is flanked by Mr Fradkov and deputy prime minister Sergei Ivanov.

In a statement, the SVR described Mr Philby as a “legendary agent and anti-Fascist, who made a vast contribution to protecting the security of our country”.

Mr Philby, who died in 1988, was a decorated member of British intelligence who worked as a spy for the Soviet Union. He was exposed in 1963 as one of the so-called Cambridge Five spy ring and fled from Beirut to Moscow.

He married Ms Pukhova while living in the Soviet Union and working as a consultant for the SVR.

The design of the bronze plaque apparently hints at Mr Philby’s double life.

It shows two images of Mr Philby in profile, one cast in relief and the other blank and hollowed out. Wearing a collar and tie, he gazes across at his mirror image, his face deeply lined.

Architect Alexei Tikhonov, who designed the memorial with sculptor Igor Novikov, told Moscow Echo radio that the memorial depicts Mr Philby as the two-headed Roman god Janus.

“It was quite a controversial decision – we were very afraid about how professionals would react to it,” he said.

Under the portrait is a quotation from Mr Philby translated into Russian saying that “I look back at the life I led as given to the service of a cause that I sincerely and passionately believe is right”.

The agency’s spokeman Ivanov said that the plaque was not unveiled to mark any particular date.

The ceremony came after Britain detained a Russian woman, Katya Zatuliveter, last week on suspicion of espionage after she worked as a research assistant for Liberal Democrat lawmaker Mike Hancock at the House of Commons.

Britain’s diplomatic relations with Russia are only just emerging from an icy period after the murder by poisoning of the dissident Russian spy Alexander Litvinenko in London in 2006.

Britain has demanded the extradition of ex-KGB agent Andrei Lugovoi in connection with Mr Litvinenko’s death but Moscow has consistently refused, citing a constitutional bar.