This was a British 57mm gun was the backbone of the British anti tank gun, and main tank gun for much of World War 2. It entered front line service in 1942 and continued in production until late 1944, and was considered to be one of the best guns in its role. Around 40000 were produced in British service.
This gun was also used by the Americans as the M1 57mm, 10000 being produced.