While the Sten gun endures to this day, it was not the first submachine gun from the UK in World War II. That honor goes to the Lanchester MkI, manufactured by the Sterling Engineering Company in Essex, England. It was designed in early 1940 by George Lanchester and was used exclusively by the British Navy throughout the war.
They were almost a direct copy of the German MP28 II except for a couple of minor changes to the basic design of the weapon. Basically the internals were the same as the MP28 with the earlier models having a repositioned selector switch that was later completely eliminated making them a fully automatic weapon only. All previously fielded SMGs were modified accordingly and remarked "Mark I *. The two unique features of this weapon is that the magazine housing was completely made from brass and the barrel jacket has a permanently attached bayonet lug on the underside for the British 1907 pattern bayonet.