Milton, who has written a number of non-fiction historical books as well as two novels, explained that he had been researching his new book when he discovered a little known document in the National Archives compiled by British scientists who had been sent to Russia to record the effects of the M Device on the Bolsheviks. “You can imagine it’s not exactly nice stuff. If you breathe it in, you start vomiting blood and you become unconscious - it’s all pretty hideous. There were endless incidents. It’s fascinating, if slightly queasy.