Instituted 24th August 1831, by Order in Council.
Branch of Service: Royal Navy
Originally awarded for 21 years exemplary conduct, but the period was reduced to 10 years in 1874, then later increased to 15 years. Bars for additional periods of 15 years were institituted by George V. In March 1981 commissioned officers of the naval services became eligible after 15 years service, provided at least 12 years were served in the ranks.