A former Soviet spy who defected to Britain will be honoured by the Queen on Thursday.
Oleg Gordievsky was a double agent during the Cold War
Oleg Gordievsky will be made a Companion of the Most Distinguished Order of St Michael and St George.
The one-time KGB colonel's honour is the same accolade held by fictional superspy James Bond.
Gordievsky, 69, who became the highest ranking Soviet spy to defect to the West, is being recognised for services to UK security.
Disillusioned with the political situation in his homeland, he operated as a double agent during the Cold War.
He first began to leak information to the West while working in Copenhagen in 1974.
He then passed on an unprecedented amount of information to British security while serving as KGB bureau chief in London.
His help led to the expulsion of 25 Soviet agents working undercover in the UK.
At the time, his defection was hailed by then foreign secretary Sir Geoffrey Howe as "a very substantial coup for our security forces".
Mr Gordievsky, who has two daughters, was MI5's greatest asset between 1982 and 1985, when his cover was blown and he was ordered back to Moscow.
In an interview last year with Time Out magazine he explained the dramatic events that led to him escaping Russia for the UK.
Sir John Scarlett was Mr Gordievsky's MI6 handler
On arriving back in Moscow he was taken into the countryside and interrogated by the KGB about being a double-agent.
Despite giving him a "truth" drug they failed to establish his guilt and released him.
He still feared for his life, however, and elaborately signalled for help from the British.
Following a pre-arranged strategy he went to an assigned lamppost on a Moscow street corner, taking a Safeway bag as a signal.
To indicate the signal had been received an English-looking man walked past chewing a Mars bar, Mr Gordievsky said.
Books on KGB
That set in motion British plans to smuggle him out of Moscow.
He took a train towards the Finnish border where he met British agents who took him across in the boot of a car.
In the UK he eventually settled in Godalming, Surrey.
He has since written a number of books about the operations of the KGB.
In 2004 he spoke out in support of Sir John Scarlett's appointment to head of MI6. Sir John had been his case officer in the early 1980s.
The CMG is used to honour individuals who have rendered important non-military services in relation to Commonwealth or foreign nations.