At the heart of much of Deighton's writing about spying and spy-craft is an acknowledgement that, even with the best of intentions, the organisations and men charged with defending the honour and safety of their respective nations are, too often, at the same time undermining the very nation they seek to protect, putting ideological or personal interest ahead of the national interest.
During the Cold War, such hypocrisy was shown up by the frequent cases of double-agents, spies like Kim Philby and John Cairncross who as intelligence officers were duty bound to protect the interests of the United Kingdom but who, in the end, sold out their countries - and their peers - for misguided ideological and personal reasons.
In Deighton's fiction, similar hypocrisies can be seen at the heart of the agencies and institutions in which many of his lead characters work. So, for example, Erich Stinnes - KGB Colonel, committed communist and adversary of Bernard Samson - is shown in Charity to in the end be a simple, drug-dealing crook contributing to East Germany's slow death. In Funeral in Berlin, each main character's motivation is as much about putting one over on the enemy - in this case, 'Harry Palmer' - as it is about protecting their nation's interests and security.
Espionage is shown in Deighton's fiction to often be a venal and corrupt place in which personal ambition, jealousy, pettiness and criminality as as much guides to characters' behaviours as training, morality and upbringing. This comes to the surface most often in the petty squabbles and irritations which mark out the office politics of secret government institutions, most effectively displayed in the daily hassles faced by Bernard Samson in Berlin Game and other books in the series.