Instituted in 1930 by King George V, and struck in silver and silver-gilt. Awarded to Commissioned Officers (CO’s) initially for 20 years service. From 1949 the qualifying period was 12 years with Clasps for additional 6 year periods of service. Wartime counted double.

Approximately 3,400 were awarded to Australians before being replaced by the National Medal in 1975.