Skeletons rattle in a secret closet

The activities of Britain's secret service, MI5, are naturally something of a mystery, but recent revelations have renewed the debate about who controls the cloak and dagger brigade.

Details have emerged of British citizens who worked as spies for East European nations during the Cold War, but most concern comes from the suggestion that when the foreign agents were discovered, MI5 decided to keep details secret from its political masters. The source of the scandal comes from documents smuggled out of Moscow following the defection of a former KGB colonel.

Vasili Mitrokhin, 77, lives in Britain under an assumed identity in a concealed location after being given asylum as reward for his information on spies who worked for the Soviet Bloc.

Colonel Mitrokhin worked in the KGB's foreign office archives from 1956 until he retired in 1984, during which time he hand-copied thousands of documents about Soviet agents recruited overseas.

When the Soviet Union collapsed in 1992 he decided to defect and presented himself to the CIA. But after the US became suspicious of his overtures he offered himself to the British, who eagerly accepted him.

Mindful of the need to enhance his pension the defector struck a deal with MI5 that after they had examined his notes he should be allowed to offer them for publication. A lucrative deal was struck, linked to newspaper and television contracts, and the past two weeks have seen news bulletins crammed with details from his archives including the names of British agents alleged to have worked for the Soviets.

The first to be revealed was an 87-year-old great grandmother who used her position as secretary at a metals research agency to pass details of Britain's nuclear weapons programme to the Soviets. But further alleged agents include two former Labour ministers and a handful of academics.