While the STEN gun endures to this day, if only as the “cheapest” full-auto machine gun that US civilians can purchase, it was not the first sub machine gun from the UK in World War II. That honor goes to the Lanchester MkI, which certainly has a familiar pattern.

With an utter lack of “gangster guns” in their arsenals, the United Kingdom was desperate to arm up with the prospect of a German invasion. According to Ian at Forgotten Weapons, the British military had nary a single sub-machine gun, despite their proven utility. Recognizing this, the British rapidly developed the capability, while starting to purchase Thompson SMGs – an expensive proposition.

Inspired by the German MP28, or rather reverse-engineered from one, the Lanchester is named after the primary engineer responsible for the weapon, George Lanchester. Lanchester worked for Sterling Engineering, which not-so-coincidentally became known for their Sterling sub-machine guns during and after the war.

The weapon was functional if a bit sparse, serving with the Royal Navy during and for decades after the war. The British Army quickly moved to the Sten, which was faster and less expensive to manufacture.

For the full story, field stripping, and details on the weapon check our Forgotten Weapons’ latest video below: