He was the last in a series of British spies whose covert action humiliated the Soviet Union’s intelligence establishment in the country when it was discovered at the height of the Cold War.

Blake was born in Rotterdam, the Netherlands in 1922, moved to England in 1942 and moved to the Dutch division of SIS in August 1944.

An entry about his life on the British government website read: „Blake returned from captivity to work for the Soviet and British intelligence, and betrayed many of the agents who were later executed, including a network in East Germany.“

British authorities arrested Blake in April 1961 and he admitted to being a double agent of the Soviet Union.

The spy was sentenced to 42 years in prison but escaped in 1966 with the help of other colleagues and two peace activists, after climbing the prison wall with a ladder made of knitting needles.

Blake was smuggled out of Britain in a cart and transported across undiscovered Western Europe, and across the Iron Curtain to East Berlin.

He spent the rest of his life in the Soviet Union and then in Russia, where he was honored as a hero.

Reflecting on his life, Blake said in an interview with Reuters in Moscow in 1991 that he believed the world was on the eve of communism.

„It was an example that could have been achieved for it was worth it,“ he said.

Russian President Vladimir Putin awarded the double agent the country’s Friendship Medal in 2007. Putin issued a statement of condolences following Blake’s death, which was posted on the Kremlin’s website.

„Colonel Blake was a brilliant professional of particular vitality and courage,“ Putin said.

„Over the years of hard and painstaking work, he has made a truly invaluable contribution to ensuring strategic parity and maintaining peace on this planet,“ the statement added.

UK authorities believe the spy khan had around 42 British agents, although Blake claimed the true number was around 600.