The General Service Medal (1918 GSM) was instituted to recognise service in minor Army and Air Force operations for which no separate medal was intended.
The GSM was equivalent to the 1915 Naval General Service Medal. Both these medals were replaced by the Campaign Service Medal in 1962.
The 1918 General Service Medal is a circular silver medal. The obverse shows the crowned effigy of the reigning monarch; the reverse bears the standing winged figure of Victory in a Corinthian helmet and carrying a trident, bestowing a wreath of the emblems of the Army (the sword) and the RAF (the wings).