The Hillingdon Battalion was formed from companies of the West Middlesex and North-West Middlesex Battalions, as part of a London District reorganisation in 1965, following local government changes. The Hillingdon Battalion was closed in 1997, with the active Companies merging with the Ealing Battalion, the Hounslow and Richmond Battalion, the Kensington and Chelsea Battalion and the Wembley and Harrow Battalion to create the West London Battalion