Britain's renegade spy David Shayler was sentenced to six months in jail on Tuesday after being found guilty of charges of disclosing secret documents and information to a British newspaper in 1997.
The 36-year-old former officer of the MI5 domestic intelligence service was sentenced by the Old Bailey court in London after it found him guilty on Monday of three charges under Britain's notoriously strict Official Secrets Act.
Two of the charges were for disclosing information and documents and one for disclosing material from a telephone tap.
In interviews with the Mail on Sunday newspaper, Shayler claimed secret services in the 1970s tapped the telephones of Labour party activists, including Jack Straw, who is now foreign secretary.
He also claimed that MI5 bungling led to its failure to prevent a 1993 Irish Republican Army (IRA) attack in central London and a 1994 attack on the Israeli embassy.
AFP