The Middlesex Regiment (Duke of Cambridge's Own) was a line infantry regiment of the British Army in existence from 1881 until 1966. The regiment was formed, as the Duke of Cambridge's Own (Middlesex Regiment), in 1881 as part of the Childers Reforms when the 57th (West Middlesex) and 77th (East Middlesex) Regiments of Foot were amalgamated with the county's militia and rifle volunteer units.

 For the campaign in France, 1939 to 1940, it was part of the General Headquarters (GHQ) Troops that could be allocated as required.

From 18 November, 1941, the 1/8th Bn was the Divisional MG Battalion to the 43rd (Wessex) Infantry Division. The 43rd (Wessex) Infantry Division was mobilised in September 1939 as a First Line Territorial Army Infantry Division.

It was converted to a Divisional MG Battalion between 01 October, 1942, and 28 February, 1944. It was also renamed the 8th Bn during this time. From the 28 February, 1944, it was converted back to a Divisional MG Battalion until the end of the War.

 During the time the 1/8th Bn was part of it, the 43rd Infantry Division was in the following theatres and battles.