The Enfield No.2 was a British revolver using the .38/200 round manufactured from 1932 to 1957. It was the standard British/Commonwealth sidearm in the Second World War, alongside the Webley Mk VI and Smith & Wesson Victory Model revolvers chambered in the same calibre.
After the First World War, it was decided by the British Government that a smaller and lighter .38 calibre (9.2 mm) sidearm firing a long, heavy 200 grain (13 g) soft lead bullet would be preferable to the large Webley service revolvers using the .455 (11.6 mm) round. While the .455 had proven to be an effective weapon for stopping enemy soldiers, the recoil of the .455 cartridge complicated marksmanship training. The authorities began a search for a double-action revolver with less weight and recoil that could be quickly mastered by a minimally trained soldier, with a good probability of hitting an enemy with the first shot at extremely close ranges. By using such a long, heavy, round-nosed lead bullet in a .38 calibre cartridge, it was found that the bullet, being minimally stabilised for its weight and calibre, tended to 'keyhole' or tumble longitudinally when striking an object, theoretically increasing wounding and stopping ability of human targets at short ranges. At the time, the .38 calibre Smith & Wesson cartridge with 200-grain (13 g) lead bullet, known as the .38/200, was also a popular cartridge in civilian and police use (in the USA, the .38/200 or 380/200 was known as the .38 Super Police load).
Consequently, the British firm of Webley & Scott tendered their Webley Mk IV revolver in .38/200 calibre. Rather than adopting it, the British authorities took the design to the Government-run Royal Small Arms Factory at Enfield, and the Enfield factory came up with a revolver that was very similar to the Webley Mk IV .38, but internally slightly different. The Enfield-designed pistol was quickly accepted under the designation Revolver, No 2 Mk I, and was adopted in 1931, followed in 1938 by the Mk I* (spurless hammer, double action only), and finally the Mk I (simplified for wartime production) in 1942.
Webley sued the British Government for £2,250, being "costs involved in the research and design" of the revolver. Their action was contested by Enfield, who stated that the Enfield No 2 Mk I was actually designed by Captain Boys (the Assistant Superintendent of Design, famous for the Boys Rifle) with assistance from Webley & Scott, and not the other way around—accordingly, their claim was denied. By way of compensation, however, the Royal Commission on Awards to Inventors awarded Webley & Scott £1,250.
RSAF Enfield was unable to manufacture enough No. 2 revolvers to meet the military's wartime demands, and as a result Webley's Mk IV was also adopted as a standard sidearm for the British Army.