Camp 020 was the specially-designed detention centre for enemy spies captured in WWII Britain.

Papers released by MI5 insist that no torture or violence was inflicted on the 480 people interned there during WWII.

But a coordinated effort was made to display the "omniscience and omnipotence" of the British Security Service, according to the wartime files.

Questioning techniques and investigative skills were drawn up by MI5 officers to create an aura of "remorseless efficiency" at Latchmere House in Ham, Middlesex - otherwise known as Camp 020.

The building itself was modified to prevent communication between inmates, and to glean as much information from them as possible during their short stay at the facility.

Listening devices were placed in cells and pipes were buried within masonry to prevent prisoners tapping Morse code to one another.

Breaking a prisoner

Suspects including Vera Erikson, passed through its doors during the course of World War II as security agents tried to gain intelligence on Nazi spying activities.

Documents released by the Public Record Office in Kew, Surrey, show that officers slowly perfected a technique to defeat their prisoners without resorting to the sadistic means attributed to their Nazi opponents.

A period of a few days to gather detailed information on the "spy" would be followed by an all-important first interrogation with up to five officers, according to the document.

It says: "The objective of the first interrogation was to obtain a break by impressing the prisoner with the hopelessness of his own position and the omniscience and omnipotence of the British Security Service."

Executed as a result of information

In those few cases where the suspect refused to capitulate, he or she would be shown obituaries of executed prisoners, the document said.

As a last resort, prisoners would also be put in solitary confinement and have all privileges, including the daily ration of three cigarettes, removed.

But the MI5 report underlines: "In spite of this apparent severity, no physical violence and no curtailment of food rations were ever applied."

Nonetheless, a total of 14 spies were executed as a result of the information they gave at Camp 020, the report notes.

Camp WX was formed for the longer term holding of prisoners, and was located successively at Stafford Prison, the Isle of Man and Dartmoor.