The BESAL is a simplified redesign of the Bren light machine gun, developed by a BSA employee named Faulkner. The design of the gun was motivated by the disastrous retreat of the British Army from Dunkirk in 1940, where they abandoned a huge amount of weaponry and war material, including most of their Bren guns.

The Bren gun was in production only as the BSA factory, which was at great risk to German bombing - and the Bren included a number of complex parts that could not be effectively put into production elsewhere in the UK on short notice. It was with this in mind that Faulkner designed the BESAL, which used much simpler components which could be made in a greta number of small shops. Decentralized production would have made it a much more resilient process in the case of invasion (similar to German small arms production late in the war).

By the time the BESAL prototypes were built, tested, and approved as being reliable and effective, however, the immediate threat of invasion had passed and the Bren was in production at the Inglis factory in Canada as well as at BSA. The BESAL design was shelved for use in case it became necessary again, but it never was.