Russian authorities announced today, Saturday, the death of the British double agent George Blake - who was spying for the KGB in the 1950s - at the age of 98.

With Blake’s death, the last of the British spies whose covert work in favor of the Soviet Union was an insult to the intelligence establishment upon its disclosure at the height of the Cold War.

Britain says that the former spy revealed the identity of hundreds of Western agents in Eastern Europe during the 1950s, and that some of them were executed as a result of Blake's betrayal.

He revealed that Blake was a Soviet spy in 1961, and was sentenced to 42 years in prison in London, but he escaped in 1966 by means of a ladder of ropes, and with the help of other prisoners and two peace activists, and he was smuggled out of Britain in a pickup truck, to covertly cross Western Europe and cross The Iron Curtain to East Berlin.

Blake spent the rest of his life in the Soviet Union and then Russia, where he was feted by heroes.

Blake was born in Rotterdam, the Netherlands, in 1922 to a Dutch mother and an Egyptian Jewish father who obtained British citizenship, and fled the Netherlands during World War II, before joining the Dutch Resistance as a messenger, and arriving in Britain in January 1943 during World War II.

Blake joined the British Navy at that time, and began working with the British intelligence service "MI6" (MI6) in 1944, then provided his services to the Soviets during the 1950s after witnessing the Americans bombing civilians in Korea.

The KGB provided the names of hundreds of agents, and revealed the existence of a secret tunnel in East Berlin that was being used to spy on the Soviets.

This is what Putin said about him

The Kremlin released a message of condolences in which President Vladimir Putin said Blake was a professional with a special degree of vigor and courage.

"During the difficult and painstaking years of work, he made an invaluable contribution to ensuring the strategic balance and peace in the world," Putin added. "The bright memory of this legendary man will never remain alive in our hearts."

"Today, the legendary intelligence agent George Blake has passed away. He sincerely loved our country and admired the achievements of our people during World War II," Russian Foreign Intelligence Service spokesman Sergey Ivanov told TASS news agency.

Blake is considered the last survivor of a generation of British spies who were successfully recruited by the Soviet Union during the Cold War.