The 77-year-old former KGB officer who unmasked Britain's "Granny spy" is a dedicated idealist, determined to bring to light his view of his homeland's failed experiment with communism.

Now living in England under an assumed name in a secret location, Russian defector Vasili Mitrokhin made it a condition of his citizenship that the notes he laboriously copied from KGB archives be published as a warning to future generations.

Long service

Colonel Mitrokhin worked in the KGB's foreign office archives from 1956 until he retired in 1984.

Over 10 years, he smuggled out 300,000 documents in his shoes to write out longhand copies at his country home. He then buried the notes in milk churns and sealed tins.

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After his defection in 1992, controversial former Secret Intelligence Service officer, Richard Tomlinson, posed as a journalist to bring out six aluminium trunks filled with Mitrokhin's notes. These are the documents which have implicated 87-year-old Melita Norwood, who passed on nuclear secrets, and disgraced former Scotland Yard officer John Symonds, 64.

Dedicated to the cause

Mitrokhin told the Times he joined the Russian secret service in 1948.

"I believed everything that we were told: we were blinkered by party propaganda."

A small, softly spoken man in a rumpled suit with a shock of thinning white hair, Mitrokhin said his disillusionment with Communism set in over a number of years.

"It was no sudden conversion. I saw the discrepancies between what they said and real life."

Eye-opener

Mitrohkin realised there was a chasm between reports on the BBC, Voice of America and Radio Liberty - which the KGB monitored - and what the people of the Soviet Union were being told.

And the archives - vast storehouses which contained a detailed record of every operation the KGB had mounted from its inception in 1917 - made for shocking reading.

Mitrokhin even came across a plot to break Rudolf Nurevev's legs after the ballet dancer defected.

"I was looking for the New Jerusalem, but we ended up at the Wailing Wall," Mitrohkin said.

Striking back

He decided to expose the Soviet empire he believed was evil, and quoted Bible passages to The Times on sin and responsibility to back up his decision.

Ever wary that by writing out the notes, he also risked signing his own death warrant, the spy kept his activities secret even from his own family.

He still will not discussed the matter with his wife.

Secret escape

When the Soviet Union collapsed in 1992, Mitrokhin decided the time had come to defect.

He first turned up on the doorstep of the CIA in the Balkans, who turned him away because they didn't believe his story. He then went to the British secret service.

Strong views

Mitrokhin: Boris Yeltsin "an old alcoholic"

Mitrokhin remained disillusioned with the homeland he left behind, and had little time for the current crop of politicians, dismissing Russian President Boris Yeltsin as an "old alcoholic".

And the KGB was still a force to be reckoned with, he said.

"They are still there. It is the same people, the same organisations, the same aims."

Although living far from Moscow, Mitrokhin feared for his life - he believed freelance assassins working for his former colleagues could be out to get him.

The truth is out there

Yet the idealism that led him to first work for, then betray, the Soviet system lingered.

George Bernard Shaw's whitewash of the Stalin's Soviet Union in the 1930s still rankles with the elderly spy.

"If a man is honest and normal, he could see that it was all built on lies. Solzhenitsyn said you can't exist on lies."