The British Submachine Gun is a type of firearm that was used by the British military during World War II. It consists of two main models, the STEN and the BREN. The STEN is a 9mm submachine gun that was developed in 1941 and was used extensively by British and Commonwealth forces throughout the war. The BREN is a .303 caliber light machine gun that was developed in 1935 and was used by the British Army until the late 1960s. Both weapons were reliable and effective, and were widely used by the British military during World War II.