Deighton attempts to show two things: First, that the "Great Game" of British intelligence (SIS) is characterized by deceit and betrayal (double and triple agents), and it presents situations which are never fully understood.

If to survive in the field, agents must be tough, cunning, adaptable, and professional; they are not glamorous and semi-divine. They can be sure only of knowing which side they are on.

They must obey their superiors, but they dare not fully trust them. Second, if the intelligence agent is of workingclass or lower-middle-class origin, he is regarded as an outsider by his upperclass superiors. They regularly come from the upper classes and have public school (i.e., private school) and elite university educations (Eton to Oxford; St. Paul's to Cambridge; Harrow to Sandhurst). If not in military uniform, they wear business suits, striped shirts, and establishment or regimental ties, light cashmere...