The Full Form of MMGS is‍ Motor Machine Gun Service.

The Motor Machine Gun Service was a unit of the British Army in the Great War consisting of batteries of motorcycle/sidecar combinations carrying Vickers machine guns. It was formed in 1914 and incorporated into the Machine Gun Corps in 1915 as the Machine Gun Corps (Motors).

Although the usefulness of the machine gun had not been fully appreciated by the British Army before the outbreak of the Great War, it soon became apparent that highly-mobile machine gun units would be of considerable value in the fluid warfare that characterized the first few weeks of the war. Accordingly, the formation of batteries of motorcycle-mounted machine guns was authorized in November 1914, under the command of Lt-Col R.W. Bradley, DSO, South Wales Borderers. These batteries were designated part of the Royal Field Artillery, one battery being allocated to the divisional Artillery of each Division of the British Expeditionary Force.^[1] Each battery consisted of 18 motorcycle/sidecar combinations, carrying six Vickers machine guns, ammunition and spare parts, eight motorcycles without sidecars, and two or three cars or trucks. The motorcycle combinations were originally Scotts, later also Royal Enfields and Clynos, the solo units usually being Triumphs.^[2] Members were recruited from Motor Cycle Clubs and other bodies of enthusiasts^[3] and officers seconded from other regiments.