1. A Secret Location

For any interrogation, a secret location is key.

In early WWII, British intelligence opened a secret interrogation centre in the millionaire enclave of Kensington Palace Gardens in London.

Requisitioning Nos. 6-7 and Nos.8 & 8a, its commanding officer Colonel Alexander Scotland stripped the mansions of their former luxury and the ‘London Cage’ was established as a grim prison.

It did not appear on any wartime lists of the Red Cross. It was the last place anyone would suspect such clandestine activity.

Today the exclusive street is home to some of the world’s most prestigious foreign Embassies.

2. Breaking a Prisoner’s Will to Resist

The main challenge facing interrogators was how to make a difficult prisoner talk. Their task was to break a prisoners ‘will to resist’.

Colonel Scotland said: ‘from time to time it was necessary to discipline tough, arrogant and imprudent prisoners. We had our methods for these types.’

An interview in the Imperial War Museum from Alfred Conrad Wernard (German prisoner from U-boat, U-187) who was held at the London Cage, reveals the use of sleep deprivation, threats of execution, interrogations every night, at different times in the night and taken blindfolded into a room for interrogation.

This particular prisoner was known to have vital information about German radar.

3. Psychological Tricks

The interrogators used various intimidation techniques and innuendos that they knew played on the ingrained German fears and psyche.

Prisoners like Alfred Wernard were in the London Cage because they had refused to give information under normal interrogations.

The interrogator slowly turned a revolver on the desk and said: ‘When it points at you, I pull the trigger.’ Out in the yard, a prisoner was shown a deep trench and threatened with being shot.

The prisoner could also be threatened with ‘Cell 14” – a grim cell in the basement.

No one was ever taken there, but the psychological threat was enough to loosen their tongues…

4. Truth Drugs

Britain’s Naval Intelligence experimented with truth drugs in December 1939 and initially tried them out on themselves.

It involved drugs like Evipan and possibly Mescaline.

Later, these were used in conjunction with hypnosis on some die-hard Nazi prisoners.

Colonel Scotland threatened to use drugs at MI5’s interrogation centre at Latchmere House, near Richmond by arriving with a syringe, ‘containing some drug or other, which it was thought would induce the prisoner to speak’ (diary of Guy Liddell, MI5).

Questions were raised by the military on whether it was morally acceptable.

John Godfrey (head of Naval Intelligence) concluded: ‘The method is justified, provided the doctors are satisfied that the technique is one that can easily be carried out, and which will have no permanent affect on the patient’s health, and the information which it is desired to elicit is of vital importance.’

5. The Walls Have Ears

The official military line was never to break the Geneva Convention during an interrogation.

One of the most effective ways of extracting intelligence from a prisoner was via microphones hidden in the light fittings and fireplaces of their room.

After interrogation, a prisoner returned to his cell and boasted to his cellmate about what he hadn’t told the interrogators, and thus he gave away some of Germany’s secrets.

6. Befriending a Prisoner

Denys Felkin of Air Intelligence and his team had interrogated thousands of German prisoners throughout WWII for the intelligence services.

He concluded that nothing works better on a prisoner than sitting him down with a bottle of whisky and packet of cigarettes.

To befriend a prisoner and become his buddy often elicited the necessary information because he gave away secrets without even realising.

That method was relatively straightforward when faced with ordinary German prisoners who were tired of war.

The challenge was extracting information from Nazi SS officers who showed no remorse for their crimes.

The London Cage was reserved for them...

The London Cage

The London Cage – Britain’s secret WWII interrogation centre – betrays a little known, but shadowy side of intelligence.

It is still be a sensitive area of intelligence past, but it has proved extraordinarily helpful in understanding the moral dilemmas and complex layers of decision-making that still face the intelligence services today.

This article highlights just six of many interrogation techniques used by the British in WWII at the London Cage.

For more in-depth detail about what went on at The London Cage, you can read more for free here.