In autumn 1940 British intelligence, MI9, opened a secret interrogation centre on behalf of in the heart of the millionaire enclave of London’s Kensington Palace Gardens. Taking over Nos. 6-7 and 8 & 8a, its commanding officer Colonel Alexander Scotland ensured that the mansion houses were stripped off their former luxury and the ‘cage’ was established as a grim prison. It soon developed a formidable reputation in military circles for any prisoner of war transferred there for interrogation. Here, Colonel Scotland and his interrogators tried “to break the prisoner’s will to resist” through periods of solitary confinement, long relays of interrogation, often at night, and sleep deprivation. Today, the declassified files – especially Colonel Scotland’s unredacted memoirs – provide a vivid insight into ‘life inside the cage’. But, proving precisely what happened there and dispelling the decades of rumours about mistreatment and torture is not straightforward.

The arrival of over a hundred SS officers in the spring of 1946 challenged interrogators to the limit. The worse SS Nazi war criminal ever held at the London Cage was SS commander Fritz Knochlein, guilty of the cold-blooded murder of surrendering British soldiers at Le Paradis (France) in May 1940. It was a horrific massacre that left its two only survivors traumatised. The orders had been given by Knochlein.

Colonel Scotland described Knochlein as: ‘A Nazi of the first order, the worst order, a German who had dedicated himself to brutality; irresponsible in the possession of power, ruthless in execution.’ But in an unexpected twist, Knochlein accused Colonel Scotland of torture and other breaches of the Geneva Convention. Knochlein’s allegations were so serious that they threatened to derail the prosecution’s case against him. The tables turned, and Colonel Scotland found himself in the dock on charges of war crimes – something for which he was ultimately cleared. But it did not prevent the rumours from continuing for decades to come.

Whatever the moral dilemmas, psychological tricks and physical conditions at the London Cage, an astonishing fact has emerged – that Colonel Scotland and his team used truth drugs on some prisoners as early as 1940. Truth drugs are generally associated with the Cold War and developed independently by the US, Britain, Russia and North Korea in the 1950s. The experimental use of drugs and hypnosis for ‘mind control’ was believed to control a person’s mind or induce them to tell the truth; hence the designation ‘truth drugs’. The subject became the focus of the Hollywood film franchise The Bourne Identity and its sequels, Aldous Huxley’s Brave New World, Arthur Koestler’s Darkness at Noon and George Orwell’s 1984. In popular culture these were seen as just fiction and pure fantasy, yet few people suspected how close to reality these accounts came.

Declassified files reveal that Britain’s Naval intelligence interrogators were experimenting with truth drugs as early as December 1939. Initially, interrogators from Naval Intelligence tried out truth drugs on their own willing intelligence officers to ascertain the effects. Bernard Trench, a Naval Intelligence interrogator attached to MI9, was one of those involved in the experimental use of drugs like Evipan, and possibly mescaline. His war diary alludes to the experimental use of drugs on prisoners. Epivan, when combined with hypnosis, could put a patient in a condition in which he would be unable to resist interrogation. The drug was traditionally used to treat types of epilepsy and certain psychotic disorders. It belonged to a group of drugs that made a person more susceptible to hypnosis. Hypnosis ensured that the patient had no memory of the interrogation.

In 1939, a Naval intelligence team (of which Trench was a part) decided to select prisoners who were known to have secret information. Their spilling of secrets in interrogation, under the influence of Epivan, would be a measure of the effectiveness of the ‘truth drug’. After two or three nights of unexplained drowsiness, the prisoner would request to see a doctor and then, as the declassified report states: ‘it would be reasonable practice for him [the doctor] to give a dose of Epivan.’ The patient would be none the wiser, would still feel sleepy and Naval intelligence could observe the effects over a longer period of time.

A doctor who was ‘prepared to adopt the technique and had no professional scruples about carrying it out’ administered the drugs to prisoners. Questions were raised at the time by the military on whether the use of truth drugs was morally acceptable. The head of Naval Intelligence, John Godfrey, 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; the information which it is desired to elicit is of vital importance.’

Turning back to Colonel Scotland, there is a reference to his use of drugs on prisoners in the diary Guy Liddell (MI5’s director of counter-espionage). It reveals that, on 22 September 1940, Colonel Scotland’s threatened to use drugs during interrogation at an MI5 interrogation centre, “Camp 020” at Latchmere House, near Richmond. The prisoner was double agent TATE (aka Wulf Dietrich Schmidt). Scotland turned up with a syringe, as the diary says, ‘containing some drug or other, which it was thought would induce the prisoner to speak’. The commanding officer, Colonel Robin “Tin-Eye” Stephens refused to allow Scotland to see TATE.

Schmidt was, nevertheless, interrogated there by MI5, finally broke under interrogation and agreed to be ‘turned’ as a double agent. He worked for the British as part of the Double Cross System that successfully turned a number of German spies to work for the Allies.

Whilst the use of torture at the London Cage cannot be definitively proved on current evidence, there is no doubt that it betrayed a, little known, shadowy side of intelligence.

Maverick and controversial, Colonel Scotland may have been, but it is hard to deny that his brilliance as an interrogator and commander of human psychology transcends even the darkest parts of the history of the London Cage.

The London Cage may 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. The importance of learning from the past was summed up in a CIA journal in which J.R. Seeger wrote: ‘This is precisely the reason intelligence professionals should read The London Cage: it is they who will be tasked to build and run future interrogations programs, and Dr Fry’s books offers an important historical analogue for the work.’ [Studies in Intelligence, vol.62, No.1, March 2018, review by J.R. Seeger].

The London Cage (Yale) by Helen Fry is now out in paperback.