Coward joined the Army in June 1924 and was captured in May 1940 near Calais while serving with the 8th Reserve Regimental Royal Artillery as Quartermaster Battery Sergeant Major. He managed to make two escape attempts before even reaching a prisoner of war camp, then made seven further escapes; on one memorable occasion managing to be awarded the Iron Cross while posing as a wounded soldier in a German Army field hospital. When in captivity he was equally troublesome to his captors, arranging several acts of sabotage while out on work details.