It is a necessary part of the spy’s modus vivendi that gives little away; deception is at the very core of his being. Today, however, more than a quarter of a century after his death, Anthony Blunt shines unprecedented light on his life as a Russian spy who, even after confessing, was allowed to continue his career at the heart of the Establishment as Surveyor of the Queen’s Pictures.

Blunt was unmasked publicly in 1979, 15 years after admitting that he was the “Fourth Man” of the Cambridge spy ring of which Guy Burgess, Donald Maclean and Kim Philby defected to the Soviet Union. After his exposure he wrote a 30,000-word memoir, which was donated anonymously to the British Library in 1984 — the year after his death — on condition that it remain closed for 25 years. Today that memoir is made public, and raises the intriguing question: even in death, can a spy ever be trusted to tell the truth? The whole truth?

Blunt describes his decision to spy for Russia, urged on by his friend and fellow agent Guy Burgess, as “the biggest mistake of my life”. He also tells how he contemplated suicide after Margaret Thatcher revealed his name in a House of Commons statement, and how he briefly considered defecting to Russia.

Mistake it may have been, but the memoir — the word “confession” can hardly apply to a document that reveals little of what he did for Russia — also makes clear that, for all his regrets, his loyalties always remained not with the country he betrayed, but with his fellow traitors.

Times Archive 1979: Professor Blunt's double life

Blunt clearly believed his confession to MI5 in 1964 and the immunity granted to him was an absolution

• Professor Blunt to break his silence

• A most distinguished traitor

• Letters: Professor Blunt and allegiance

RELATED LINKS

• How I got Anthony Blunt to come out of hiding

• Blunt’s memoir a sorry tale without remorse

MULTIMEDIA

• ARCHIVE: how Times got Blunt to talk in 1979

• GRAPHIC: the Cambridge spy ring

At the centre of it all was Burgess, the flamboyant homosexual whom Blunt met in the heady days of Cambridge in the 1930s. Burgess was an undergraduate, Blunt a don at Trinity, and the older man did not immediately take to the irrepressible student. He was soon won over, however. “He could be perverse both in argument and in behaviour, but in the former he would wriggle back to sense and in the latter he would apologise in such an engaging manner that it was difficult to be angry for long,” Blunt wrote.

Blunt, who was also homosexual, insisted that there was nothing sexual in their relationship. He could not resist, however, being swept up in Burgess’s burgeoning enthusiasm for left-wing politics, which had gained an “almost a religious quality” among the students.

As fascism took hold in Europe, Blunt decided that he had to take sides. But Burgess was one step ahead, and when Blunt was invited to join the Communist Party, Burgess urged him not to do so, but to join him in working for the NKVD, the forerunner of the KGB. “I was thus faced with the most important decision of my life,” he wrote. “I might have joined the Communist Party, but Guy, who was an extraordinarily persuasive person, convinced me that I could do more good by joining him in his work. What I did not realise at the time is that I was so naive politically that I was not justified in committing myself to any political action of this kind.

“The atmosphere in Cambridge was so intense, the enthusiasm for any anti-fascist activity was so great, that I made the biggest mistake of my life.”