Our kind of traitor Britain has endured a series of embarrassing spy scandals in the past century

Recruited by the Soviet Union while studying at Cambridge, the group included Donald Maclean, who was a diplomat around the globe, and Guy Burgess, who held a senior role in the Foreign Office.

Their defection in 1951 dealt a blow to the reputation of British intelligence, but this was overshadowed when Kim Philby, once MI6’S senior officer in the US, fled to Moscow in 1964 after years of treachery.

The ring also included Anthony Blunt, the Queen’s art adviser.

Ray Mawby

His spy activities remained a secret until long after his death in 1990, but Mawby, who was a Conservative MP between 1955 and 1983, spent years in the pay of Czechoslovakian intelligence.

Secret files unearthed in 2012 found that Mawby, given the code name Laval, handed over information including a floorplan of the Prime Minister’s office in the House of Commons in the 1960s.

George Blake Another spy deeply embedded in MI6 during the Cold War, Blake’s betrayal over the course of nine years compromised at least 40 MI6 agents in Eastern Europe.

He was jailed in 1960, but managed to escape in 1966 to

Russia, where he died in December last year, aged 98.

Geoffrey Prime Prime betrayed secrets to the KGB while working on RAF intelligence duties in West Berlin in the 1960s. He later worked for GCHQ, where he continued to pass sensitive information to his handlers.

Prime was convicted in the early 1980s of espionage and child sexual abuse, and was imprisoned until 2001.