Between the World Wars

The Royal Marine Artillery (RMA) and Royal Marine Light Infantry (RMLI) were amalgamated on 22 June 1923. Post-war demobilisation had seen the Royal Marines reduced from 55,000 (1918) to 15,000 in 1922 and there was Treasury pressure for a further reduction to 6,000 or even the entire disbandment of the Corps.

As a compromise an establishment of 9,500 was settled upon but this meant that two separate branches could no longer be maintained.

The abandonment of the Marine's artillery role meant that the Corps would subsequently have to rely on Royal Artillery support when ashore, that the title of Royal Marines would apply to the entire Corps and that only a few specialists would now receive naval gunnery training.

As a form of consolation the dark blue and red uniform of the Royal Marine Artillery now became the full dress of the entire Corps. Royal Marine officers and Senior NCO's however continue to wear the historic scarlet in mess dress to the present day. The ranks of Private, used by the RMLI, and Gunner, used by the RMA, were abolished and replaced by the rank of Marine.