Peter Cottrell grew up in South Wales. He joined the Territorial Army whilst still in the sixth form and after qualifying as a teacher, was commissioned into the Royal Navy in 1988. He later transferred into the army's Educational and Training Services Branch, specializing in teaching military history and international relations. He retired in 2008 to teach English, history and classics and to pursue a career in writing. His first novel, England's Janissary, was also published by Robert Hale.