In his book Empire Of Secrets, intelligence historian Calder Walton reveals that Scots MI5 officer Alex Kellar broke up a London-based cell of Jewish extremists who planned to launch a bombing campaign in 1948.
With the benefit of newly released MI5 files Mr Walton has been able to shed new light on Mr Kellar's role in dismantling an Irgun terror cell operating in the UK in the late 1940s.
After studying law at Edinburgh University, Mr Kellar was recruited into MI5 in the 1930s. In 1948 he became head of MI5's counter-subversion unit, one of his main tasks being to investigate the activities of the Irgun and Stern Gang terrorist groups.
Kellar's investigation led to an Irgun team, based in East London, which was planning to attack British troops as they arrived home from Palestine. After three weeks of surveillance on one of its members, a young Jewish grocer and committed Zionist called Monte Harris, Kellar ordered Special Branch to raid his shop in Aldgate.
The search unearthed sufficient ingredients to make a substantial number of thermite incendiary explosives. Harris was convicted of conspiracy to commit terrorist acts and sentenced to seven years, although he was released after serving just two.
After retiring from the Security Service in the late 1960s, Mr Kellar went on to work for the Tourist Board.