Motor cycle despatch riders and armoured cars were used from the earliest days of the war, most notably by the Royal Naval Division.

Army Order 480, dated 12th November 1914 and sanctioned in February 1915, approved the addition to each Division of a motor machine gun battery. This was designated to be a unit of the Royal Field Artillery and was known as the Motor Machine Gun Service. Men were found from the volunteers, or by special enlistment of men known to be actively interested in motorcycles (such as cycle club members). The Coventry offices of the enthusiasts magazine Motor Cycle was listed as a recruiting office for the MMGS.

A MMG Squadron joined the Royal Naval Division on 17 March 1915, and served with it on Gallipoli in April and May 1915.

By the opening of the Battle of Loos on 25th September 1915, there were 18 MMG Battalions with the BEF, of which 2 were Canadian. 5 were engaged at Loos. The MMG battery consisted of mobile machine guns, mounted for the most part on motor cycle side-cars.

The creation of the MGC in October 1915 incorporated the Motor Machine Gun service, which became known as the Machine Gun Corps (Motors). At this time the MGC(M) had around 3000 men.

Batteries of the MMGS included 18 cycle/sidecar combinations, carrying 6 Vickers machine guns with ammunition and spare equipment; 8 motorcycles without sidecars; 2 or 3 wagons or cars; and a sidecar combination for the officer commanding.

By May 1916, most of the batteries had been withdrawn from Divisional command and attached as Corps Troops.

From late 1916, many men of the MGC(M) transferred to the Heavy Section, MGC (later to be known as the Tank Corps). In 1922, the Tank Corps absorbed the MGC(M) completely.

Earliest models were Scotts, with Matchless, Premier, Zenith, Enfield and Clyno machines entering service after the Scotts were shown to be insufficiently robust for active service.

Men of the MMGS and MGC(M) wore an unusual uniform with leather gaiters in place of puttees, and with goggles, gauntlets and weatherproof garments for use while riding (but no crash helmet). Cap badges were similar to the MGC, but with MMG lettering. The shoulder title was a brass MGC with the letter M beneath. A khaki arm patch with the words Motor Machine Gun picked out in red was also worn on the tunic.

Once the fighting on the Western Front had settled down (by late 1914) the opportunities for motor machine gun units to operate as a mobile force were limited indeed. In many cases they had to operate as conventional machine-gun sections. However, they came into their own once again during the great advances beginning with the Battle of Amiens on 8 August 1918.

Elsewhere, and most particularly in Egypt, Palestine, East Africa and Mesopotamia, the mobility of the units was of great value and they saw considerable action in these theatres.