The XL64 Individual Weapon (IW), also known as the Enfield Weapon System (EWS), was a prototype assault rifle designed by RSAF Enfield.
The XL64 IW was designed in the mid-1970s at Enfield as an attempt to create a service rifle chambered for an intermediate calibre after it was decided that 7.62x51mm NATO was impractical for use with assault rifles. Enfield settled on the 4.85mm cartridge, since it could deliver high volumes of fire with lower recoil. However, NATO decided to adopt the 5.56 cartridge instead and the 4.85mm was abandoned. The British Army could not accept a new service rifle chambered for their own cartridge without causing a storm of controversy, and so the XL64 was abandoned, along with the light support weapon variant, the XL65 LSW. It did, however, provide a design that would later become the SA80, the current British service rifle.
The XL64's design was perhaps inspired by the earlier experimental EM-2 rifle, but internally it was not dissimilar to the AR-18. This lead to accusations that Enfield had copied Sterling's AR-18 variants in the 1980's, and prompted Sterling to create the Sterling Bullpup in response to the controversy.