The Lanchester is a British submachine gun that was formerly in service with the Royal Air Force and Royal Navy. It was produced during World War II in response to Britain's initial lack of submachine guns.
After the disastrous military campaign in France and the evacuation from Dunkirk in June 1940, the British Ordnance Board realized that Britain's small arms arsenal was sorely lacking compared to Germany's and they expressed an immediate desire for an indigenous equivalent to the German MP 38 submachine gun. The British Expeditionary Force had trialed a series of submachine guns in France the previous year and selected the Thompson, which was now being equipped to the Army. However, the imminent threat of a German invasion led the Air Force to demand a similar weapon to defend its airfields. Initially they demanded 10,000 British-made copies of the MP38, but this proved impossible so the order was changed by the Ministry of Supply to 50,000 copies of the MP 28. Sterling Armaments of Dagenham were given 4 months to produce a batch of prototypes. The project was headed by George Herbert Lanchester, from whom the finished weapon eventually got its name.
Two prototypes were tested on the 8th and 13 November 1940. They were, as requested, clones of the MP28. The first prototype proved unsatisfactory and encountered stoppages when using ammunition supplied by Winchester and Imperial Chemical Industries. The second prototype functioned perfectly fine with all the ammunition tested and the weapon was accepted for troop trials.
Endurance trials were scheduled on the 28th of November 1940 and were overseen by Major Reginald V. Shepherd. The gun was now in its fourth prototype and went through 5,204 rounds of ammunition with very few stoppages. It passed all the "torture" tests and functioned with almost every type of 9×19mm cartridge, with the exception of those made by Beretta. It was decided by the Ordnance Board to adopt the weapon as the Lanchester Mk.I and production rights were handed over to the Royal Navy.
The Lanchester was immediately pressed into service with the Air Force and Navy, where it replaced the hazardously unreliable Smith & Wesson Light Rifle. The Lanchester was never widely issued to the Army, whose requirements were fulfilled by American-supplied Thompsons and later the British-made Sten. In 1941, the Navy designed a more cost-efficient variant of the Lanchester, known as the Mk.I*, which simplified production by removing the fire selector, changing the sights, and redesigning the trigger mechanism. Production of the Mk.I* superseded the standard Mk.I, and many existing Mk.Is were converted into Mk.I*s.
The Lanchester was officially retracted from Naval service in 1960, although some guns were still issued past that date.
George Lanchester also developed a stripped-down model of the weapon for the Army, but it was rejected in favor of the Sten in 1941.
The Lanchester was a simple blowback-operated submachine gun entirely based on the Bergmann MP28/II. It fired from an open bolt and cocked from the right side. The only major difference in design was the addition of a fire selector, in the form of a small lever, located just in front of the trigger. This feature was deemed unnecessary and removed in the Mk.I* version.
The standard of manufacture was good. Owing to its manufacture by the Navy, brass components were used to make up the magazine feed. The gun was very heavy and solidly-built. 50-round magazines were used, and fed into the left side of the receiver.