Instituted by King George V in 1919 to mark the end of World War I and record the service given. The British War Medal 1914-20 was awarded as follows:
Navy: For 28 days mobilised service in Australia, at sea or overseas during prescribed periods.
Army: Having entered theatres of war during specified periods or left places of residence and rendered approved service overseas.
Mercantile Marine: Awarded to the men and women of the Mercantile Marine who served at least six months at sea between 4th August 1914 and 11th November 1918. Licensed Pilots, Fishermen and crews of Pilotage and Lighthouse Authorities' Vessels, and of Post Office Cable Ships were also eligible.
Those eligible also included members of women's organisations; persons on the staffs of military hospitals and members of recognised organisations who handled sick and wounded; and members of other duly recognised or other authorised organisations as specified in medal regulations.
The qualification period of service between 5 August 1914 and 11 November 1918 was later extended to cover post-war mine clearance and service in Russia during 1919 and 1920.