UK intel files shed new light on famed Cold War spy cases

Fresh details of some of Britain's biggest Cold War spy scandals, including the network of Soviet agents who stole naval intelligence secrets, emerged in newly released secret files Tuesday.

The Portland spy ring, believed to have helped the Soviet Union build a new class of submarines in the 1960s, marked a turning point in Cold War espionage in Britain, say historians.

The network was run by Konon Molody, a deep-cover KGB officer posing as a Canadian businessman named Gordon Lonsdale.

Since he lacked the diplomatic immunity given to intelligence personnel using genuine identities, he was arrested and sentenced to 25 years in prison for espionage in 1961.

This was the first time Britain's MI5 domestic intelligence service unearthed an "illegal" spy running other operatives.

MI5 files released by the National Archives reveal how, during a series of prison interviews, Molody offered to disclose information and even to become a double agent, in return for his release.

"He wished... to make a deal with us," said a 1961 MI5 memo.

"Lonsdale's own idea was that he might be exchanged for some British agents held by the Russians, or even that he might be allowed to escape."