Sten gun

The STEN (or Sten gun) was a family of British 9 mm submachine guns used extensively by British and Commonwealth forces throughout World War II and the Korean War. They were notable for having a simple design and very low production cost making it an effective insurgency weapon with resistance groups. Over 4 million Stens in various versions were made in the 1940s.

Sten gun in Worldwar
The Sten saw a lot of action against the Race when they invaded England in 1943, and even against the British themselves in Palestine by Jews Rebels.