William Ewart Fairbairn 28 February 1885 - 20 June 1960) was a British Royal Marine and police officer. He developed hand-to-hand combat methods for the Shanghai Police during the interwar period, as well as for the allied special forces during World War II. He created his own fighting system known as Defendu. Notably, this included innovative pistol shooting techniques and the development of the Fairbairn-Sykes Fighting Knife.