20/06/2013 12:49 BST | Updated 19/08/2013 06:12 BST

A London Landmark: The Workplace of Al-Qaeda's Favourite Psychiatrist

When people visit the IMAX or the South bank centre they may be dimly aware of being overlooked by a lovely red brick Victorian building. The lettering on the front identifies its original purpose: The Royal Waterloo Hospital for Children and Women. Few will realize that they are passing one of London's most sinister landmarks. It was here that Dr. William Sargant - arguably the most powerful and influential psychiatrist of his generation - ran Ward 5, otherwise known as the sleep room: an experimental treatment unit that has become a byword among conspiracy theorists.

William Sargant was a larger than life character: a big man with a big profile. He was a media psychiatrist before people did such things, a best-selling author, a Royal Society of Medicine president, a founding member of the World Psychiatric Association, the head of the department of psychological medicine at St. Thomas's, and a champion of novel treatment methods; however, if you read any history of modern British psychiatry, you'll find that he isn't mentioned. Neither is the sleep room. Both are regarded as something of an embarrassment.

Narcosis (or deep sleep therapy) was originally developed in the 1920s and involved putting patients to sleep for months at a time. Sargant was a keen advocate and made certain modifications to the procedure, such as administering extremely high doses of chlorpromazine (a major tranquilizer) and adding three sessions of ECT (shock therapy) per week. The purpose of this radical intervention was to erase those bad memories that were supposed to be a root cause of mental illness. The problem was, of course, that good memories were erased along with the bad ones. Some of his ex-patients have been traced, and when interviewed, they claim that he quite literally wiped their brains clean.

It has been suggested that the sleep room wasn't a treatment unit at all, but an experiment conducted on behalf of the CIA (an organization who were, at that time, extremely interested in brainwashing and the possibility of extirpating memories). Sargant certainly had links with the British secret service. Indeed, he was once described as MI5's in-house psychiatrist. Even though treatments like narcosis and ECT fell out of favour in the more liberal atmosphere of the 1960s, the sleep room survived into the 1970s. It would be interesting to examine the medical records of the individuals Sargant treated; however, this isn't possible, because he destroyed all the relevant files before his retirement - a fact that has served only to fuel speculation concerning the true nature of his activities.

The actress Celia Imrie was treated by Sargant when she was fourteen. She claims that he still features in her nightmares: a cold man with 'evil eyes'. Professor Malcolm Lader, one of the country's leading experts on psychopharmacology said of Sargant, 'There was a whiff of sulphur about him.' Does anybody read his work now? Well, yes. A translation of his best-selling book on brainwashing is said to have been found in an Al-Qaeda training camp in Afghanistan. A fitting tribute.