Background: The Distinguished Service Medal (DSM) was established on 14 October 1914 as a Level three military decoration for award to personnel of the Royal Navy and members of the other Services up to and including the rank of Chief Petty Officer, for bravery and resourcefulness on active service at sea. Since 1993 the DSM is no longer awarded

Design: The DSM is a circular, silver medal, 36mm in diameter. The obverse bears the crowned effigy of the reigning monarch. The reverse has the inscription ‘FOR DISTINGUISHED SERVICE’ in three lines, within a laurel wreath surmounted by an Imperial crown. The ribbon is 1.25 inches wide and consists of three equal vertical stripes of dark blue, white and dark blue, with a thin dark blue stripe down the centre of the white. The medal is hung on a plain and straight suspender.

Bars: Subsequent acts of gallantry which would have merited an award of the DSM were awarded a bar to be worn across the ribbon. Bars issued during WW1 were dated on the reverse, while those awarded during WW2 were undated.