Blake’s secret work for the Soviet Union repeatedly undermined British intelligence, and led to the deaths of dozens of western operatives.
As an MI6 mole, he exposed the identities of hundreds of agents working in eastern Europe in the Fifties, many of whom were then executed on Moscow’s orders.
When he was finally unmasked as a Soviet spy in 1961, he could breathe easy knowing he would not face such capital punishment. Instead, he was sentenced to 42 years in London’s Wormwood Scrubs prison.
But he escaped five years later with the help of two peace activists, and was smuggled out of Britain in a camper van.
He spent the rest of his life in Russia, where he remains, to this day, feted as a hero.
Announcing his death on Boxing Day, Sergey Ivanov, spokesperson for the SVR foreign intelligence agency, said: “The bitter news has come – the legendary George Blake is gone. He died of old age, his heart stopped.”
Yet here, his crimes – and the deaths they led to – have remained a matter of official revulsion.
When an appeal was made to Tony Blair in the early Noughties to allow Blake to visit the UK to see his grandchildren, the then prime minister told the spy’s supporters that should he travel to the UK, or any other country in western Europe, he would be immediately arrested.
Blake, who was born in Rotterdam in 1922, joined the British Secret Intelligence Service, MI6, in 1944 after fleeing to the country during the Second World War.
After the war, he studied Russian at Cambridge University before being sent to Seoul in 1948 where he gathered intelligence on communist North Korea, communist China and the Soviet Far East.
But he turned traitor after being captured, imprisoned and indoctrinated by North Korean troops in 1950.
Upon his release, MI6 dispatched him to divided Berlin, where he first started sharing western secrets with Russian officials.
“I met a Soviet comrade about once a month,” he said in a 2012 interview. “I handed over films and we chatted. Sometimes we had a glass of Tsimlyansk champagne.”
Perhaps his greatest coup was to report the building of a secret underground tunnel in the scissored German city, running from the American sector into the Soviet zone, which allowed western agents to tap underground cables and listen to Russian communications.
Why did he do it? Because communism, he said in a 1991 interview, was “an ideal which, if it could have been achieved, would have been well worth it”.
He added: “I thought it could be, and I did what I could to help it, to build such a society. It has not proved possible. But I think it is a noble idea and I think humanity will return to it.”
It was only in 1961 that his crimes were discovered.
A Polish defector revealed there were moles at the heart of British intelligence but while clues led to Blake, the idea was considered so preposterous by his MI6 bosses that they waved it away. Only six months later, when the wife of one of his Berlin drinking buddies also fingered him as a double agent, did the web of deceit unravel and he was arrested.
When he escaped from Wormwood Scrubs in 1966, he left behind his wife, Gillian, and three children.
He married a Soviet woman, Ida, with whom he had a son, Misha; took a Russian name Georgy Ivanovich; and worked at a foreign affairs institute before his retirement.
He was honoured by Vladimir Putin in 2007 and held the rank of lieutenant colonel in the former KGB.
Crucially, for the rest of his days, he maintained that what he had done, ultimately, was the right thing. “Looking back on my life,” he said in an interview to mark his 90th birthday, “everything seems logical and natural.”
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies