As the aviation correspondent for the London "Evening News", Tangye covered the Spanish Civil War. His 1937 account of the war, "Red, White and Spain", provided a strongly pro-Nationalist viewpoint. However, Tangye later recorded that it had been ″written by the author as a cover to his assignment by MI5 as a secret agent in the Spanish War″ seeking information on German military involvement. There is independent evidence that he worked in MI5’s press department, later acting briefly as its director.