William E. Fairbairn in the context of Lieutenant colonel (United Kingdom)

The Fairbairn–Sykes fighting knife is a double-edged fighting knife resembling a dagger or poignard with a brass or wooden foil grip. It was developed by William Ewart Fairbairn and Eric Anthony Sykes in Shanghai based on ideas that the two men had while serving on the Shanghai Municipal Police in China before World War II.

The F-S fighting knife was made famous during World War II when issued to British Commandos, the Airborne Forces, the Special Air Service (SAS) and many other units, especially for the Normandy landings in June 1944. With its acutely tapered, sharply pointed blade, the F-S fighting knife is frequently described as a stiletto, a weapon optimised for thrusting, although the F-S knife can be used to inflict slash cuts upon an opponent when its cutting edges are sharpened according to specification. The Wilkinson Sword Company made the knife with minor pommel and grip design variations.

Major Eric Anthony Sykes (5 February 1883 – 12 May 1945), born Eric Anthony Schwabe, was a soldier and firearms expert. He is most famous for his work with William E. Fairbairn in the development of the eponymous Fairbairn–Sykes fighting knife and modern British Close Quarters Battle (CQB) martial arts during World War II. Originally working for an import/export company selling weapons in East Asia, he claimed he volunteered for and served in the British Army as a sharpshooter on the Western Front during World War I. Returning to China in 1917, he joined the volunteer branch of the Shanghai Municipal Police (SMP) Specials with the rank of Inspector in 1926.