In Britain, thousands of soldiers and service personnel have participated in secret experiments involving toxic agents.
Questions remain as to the extent to which these trials were harmless, or may have left a lasting legacy on people who suffered more serious effects from the drugs they were given.
Professor Ulf Schmidt has written a book Secret Science: A Century of Poison Warfare and Human Experiments which traces the history of chemical and biological weapons research. Below, we feature from one such experiment.
In this original footage from the Moneybags Trial 1964, participants from 41 Royal Marine Commando were tasked with engaging in a field exercise after being given the hallucinogenic drug Lysergic acid diethylamide, or LSD at Porton Down.
The video documents their experience over a week-long period between the 27th November to the 4th December 1964.
The aim of the trial was to test the effect of drug LSD 25 on behaviour of troops in field conditions:
After the ordeal, according to a description by the Imperial War Museum one Royal Marine "was in a state of distress and comforted by [a] nurse, while others smiled and laughed hysterically, one attempting to cut down a tree with his spade, and another climbing the tree."
Upsettingly, one very distressed Marine is held by a duffel coated doctor and scientist, muttering "I am not going to die."
In 2006 MI6 paid out thousands to ex-servicemen for tests conducted in the 1950's and 60's such as the one featured above.