Fearing that the MI6 has been penetrated by the recent defections of agents to the USSR, the deputy head of MI6, MacGillivray needs to turn to someone who is not on any list of MI6 staff.

He turns to Jason Love, a West Country doctor who had done some intelligence work for MacGillivray in India during World War II.

Together they discover a communist plot to assassinate the pro-British Shah of Iran during a visit to Persepolis, thereby threatening Britain's Eastern oil treaties.

The idea of the reluctant amateur spy also came from Leasor’s time as a foreign correspondent during the 1950s, when it was common for journalists to be asked to do small unofficial, and therefore deniable, jobs by members of the British intelligence community.

In 1966 it was made into a British film Where the Spies Are directed by Val Guest and starring David Niven, Françoise Dorléac and John Le Mesurier.

[1] In 2019 it was made into an audio drama by Spiteful Puppet starring George Lazenby, Terence Stamp, Michael Brandon, Glynis Barber and Nickolas Grace.