In 1940 Proudfoot was conscripted into the Royal Air Force (RAF). After a mixed career in the RAF, Proudfoot became an NCO and served in the education branch where he was responsible for providing basic instruction in English, mathematics and technical skills to new recruits, many of whom came from an educationally disadvantaged background. As a Training Instructor he "… taught hundreds of conscripts stuff they weren't really bothered about. He took it as a challenge to interest them and keep them entertained – an achievement he still remembers with pride" – from the Proudfoot School of Hypnosis website.