The interrogation of captured suspects has always been an essential - and controversial - element in counter-espionage and counter-terrorist work. Different generations have faced this challenge in different ways, but all have faced a consistent issue: how to persuade a detainee to disclose reliable information in a useful period of time.
During the Second World War and its aftermath, when Britain was seeking to stabilize and denazify Germany, the Security Service played a key role in managing detainee interrogations. This effort, however, was accompanied by controversy which culminated in a scandal involving a British interrogation centre at Bad Nenndorf, Germany.
Camp 020 and 'Tin Eye' Stephens
Lt Col Robin "Tin Eye" Stephens, the Commandant of Camp 020
During the war, the Security Service established an interrogation centre in Britain, Camp 020, in which captured German agents were interrogated and 'broken'. Based in Latchmere House in south London, Camp 020 played a key role in the Security Service's now legendary 'Double Cross System'.
It achieved successes that were unprecedented in the history of warfare. The Security Service detected every wartime German spy who arrived in Britain and turned many of them into double agents.
Camp 020's function, however, was not simply confined to the 'Double Cross System'. The camp also provided useful information for Allied codebreakers at Bletchley Park. And in the closing stages of the war, it was responsible for 'breaking' several captured Nazi leaders - some of whom were then successfully tried by the Allies at Nuremberg.
The camp was run by Lt. Col. Robert 'Tin Eye' Stephens. By all accounts, Stephens was a formidable character who had an extraordinary ability to break even the hardest of spies. 'Tin Eye' - so called because of his thick monocle - used every kind of available 'mental pressure' to 'break' prisoners.
Much like Stephens himself, Camp 020 made for an ominous first impression. The camp was not designed for prisoners of war (POWs), but rather for captured civilian agents (spies). The Geneva Convention relates only to POWs and so did not apply to Camp 020, nor was it listed by the Red Cross. However, contemporary Security Service records - written without the intention of ever being declassified - reveal that Stephens persistently took a hard-line approach against the use of physical violence in interrogations.
'Violence is taboo', wrote Stephens in his in-house history of Camp 020 now available as a National Archives publication, "for not only does it produce answers to please, but it lowers the standard of information" . Stephens put the unprecedented successes of Camp 020 down to the rule of non-violence. "Never strike a man" wrote Stephens in instructions for interrogators. "In the first place it is an act of cowardice. In the second place, it is not intelligent. A prisoner will lie to avoid further punishment and everything he says thereafter will be based on a false premise".
Stephens' orders are supported by other contemporary records, such as the diary of Guy Liddell, a future Deputy Director-General of the Security Service. These records show that Stephens sometimes went to extraordinary lengths to outlaw physical violence at Camp 020. On one occasion in September 1940, Stephens expelled a War Office interrogator from the camp for hitting a prisoner, the double agent TATE. As Liddell noted in his diary "It is quite clear to me that we cannot have this sort of thing going on in our establishment. Apart from the moral aspect of the whole thing, I am quite convinced that these Gestapo methods do not pay in the long run". Stephens saw that the officer in question never returned to Camp 020.
At the end of the war, Stephens was posted to occupied Germany, where he was placed in charge of a new interrogation centre based at Bad Nenndorf, a spa town near Hanover in Lower Saxony. Stephens was the obvious choice to run the German camp: he had more experience of interrogating prisoners, and had more success in doing so, than anyone else in the British intelligence community.
 Camp 020: MI5 and the Nazi Spies, ed. Oliver Hoare. Public Record Office (2000). ISBN 1903365082