Oleg Gordievsky, UK's Cold War spy inside the KGB, dies

Police said on Saturday that they are not treating his death as suspicious.

Historians consider Gordievsky one of the era's most important spies.

In the 1980s, his intelligence helped avoid a dangerous escalation of nuclear tensions between the USSR and the West.

Born in Moscow in 1938, Gordievsky joined the KGB in the early 1960s, serving in Moscow, Copenhagen and London, where he became KGB station chief.

He was one of several Soviet agents who grew disillusioned with the USSR after Moscow's tanks crushed the Prague Spring freedom movement in 1968, and was recruited by Britain's MI6 in the early 1970s.

The 1990 book KGB: The Inside Story, co-authored by Gordievsky and British intelligence historian Christopher Andrew, says Gordievsky came to believe that "the Communist one-party state leads inexorably to intolerance, inhumanity and the destruction of liberties".

He decided that the best way to fight for democracy "was to work for the West".

He worked for British intelligence for more than a decade during the chilliest years of the Cold War.

In 1983, Gordievsky warned the UK and US that the Soviet leadership was so worried about a nuclear attack by the West that it was considering a first strike.

As tensions spiked during a NATO military exercise in Germany, Gordievsky helped reassure Moscow that it was not precursor to a nuclear attack.

Soon after, US President Ronald Reagan began moves to ease nuclear tensions with the Soviet Union.

In 1984, Gordievsky briefed soon-to-be Soviet leader Mikhail Gorbachev ahead of his first visit to the UK — and also briefed the British on how to approach the reformist Gorbachev.

Gorbachev's meeting with Prime Minister Margaret Thatcher was a huge success.

Ben Macintyre, author of a book about the double agent, The Spy and the Traitor, told the BBC that Gordievsky managed "in a secret way to launch the beginning of the end of the Cold War".

Gordievsky was called back to Moscow for consultations in 1985, and decided to go despite fearing — correctly — that his role as a double agent had been exposed.

He was drugged and interrogated but not charged, and Britain arranged an undercover operation to spirit him out of the Soviet Union — smuggled across the border to Finland in the trunk of a car. 

He was the most senior Soviet spy to defect during the Cold War.

Documents declassified in 2014 showed that Britain considered Gordievsky so valuable that Thatcher sought to cut a deal with Moscow: If Gordievsky's wife and daughters were allowed to join him in London, Britain would not expel all the KGB agents he had exposed.

Moscow rejected the offer, and Thatcher ordered the expulsion of 25 Russians, despite objections from Foreign Secretary Geoffrey Howe, who fared it could scuttle relations just as Gorbachev was easing the stalemate between Russia and the West.

Moscow responded by expelling 25 Britons, sparking a second round in which each side kicked out six more officials. But, despite Howe's fears, diplomatic relations were never severed.

Gordievsky's family was kept under 24-hour KGB surveillance for six years before being allowed to join him in England in 1991.

He lived the rest of his life under UK protection in the quiet town of Godalming, southwest of London.

In Russia, Gordievsky was sentenced to death for treason.

In Britain, the Queen appointed him a Companion of the Order of St Michael and St George in 2007 for "services to the security of the United Kingdom".

In 2008, Gordievsky claimed he had been poisoned and spent 34 hours in a coma after taking tainted sleeping pills given to him by a Russian business associate.