Instituted in July 1919, the British War Medal initially honoured service abroad between 5 August 1914 and 11 November 1918. Eligibility was later extended to include service in Russia and mine clearing at sea until 1920.
Unlike the 1914 Star and the 1914–15 Star, the British War Medal could be awarded to all military personnel who had served during any stage of the war, or who had died on active service.
Some 6,660,000 British War Medals were awarded, including 159 to sitting MPs and 216 to Peers.
The medal in the Parliamentary collection was awarded to Sir Arnold Wilson (1884−1940), who served in the Persian Gulf as a political officer, soldier and senior administrator between 1909 and 1920.
In 1933 Wilson became Conservative MP for Hitchen. He held the seat until he died while serving in the Royal Air Force during the Second World War. Wilson is the only parliamentarian whose awards have been incorporated into Parliament's collection of medals and coins.