With the outbreak of the Second World War, Ashton joined the Metropolitan Police in which he served during the Blitz. He also gained a scholarship for the Royal Academy of Music, where he studied singing every other day and where he met his future wife, Elizabeth Cooper, who was also studying singing. He was then drafted into the army where he served for two and a half years. During that time he worked in a secret department, based in the Natural History Museum and headed by Charles Fraser-Smith, whose task was to create concealed weapons and gadgets – "exploding fountain pens and umbrellas which fired poison darts" as Ashton recalled – for use by undercover operatives serving behind enemy lines in occupied Europe. The author Ian Fleming is known to have taken an interest in that department's work, later basing 'Q' division in his James Bond novels on the activities he saw there.