In the years after World War One, the British military wanted a new machine gun, and they wanted it to replace both the Lewis and the Vickers. Through the 1920s the British would tinker with most of the light machine guns that became available, but it was not until the early 1930s that a serious formal trial was conducted. The initial trials found three particularly encouraging guns; the ZB-26, Madsen, and Vickers-Berthier. Over a series of followup testing, the Madsen and Vickers-Berthier were both eliminated, leaving the Czechoslovakian ZB as the final choice.

The British were extremely enthusiastic about the qualities of the ZB, and it is understandable why. The final .303 British version, the Bren, is widely regarded as the best magazine-fed light machine gun ever made. In its final preproduction trial, one of the prototype guns endured a 150,000-round trial without any real problems.

The design was licensed for British production as well as in the Dominions, and would be put into production at both Enfield in England and the John Inglis company in Canada. About 30,000 were produced before the Dunkirk disaster, which would lead to simplification of the design. But those changes are a subject for another video later...