[2][4] One or more voyages through a danger zone during the war qualified a mariner for the award of the medal, as did service at sea for not less than six months between 4 August 1914 and 11 November 1918.

Men who served in coastal trades, such as pilots, fishermen and lightship and post office cable ship crews could also qualify.

[2][4][9] The obverse is identical to that of the British War Medal and shows Sir Bertram Mackennal's bareheaded effigy of King George V facing left, with the legend "GEORGIVS V BRITT: OMN: REX ET IND: IMP:" (George V, King of all the British Isles and Emperor of India).

[2][4][5] The reverse, designed by Harold Stabler, shows a merchant steamship ploughing through heavy seas, with an enemy submarine sinking on portside and a sailing ship in the background.

The Memorial Plaque is a medallion designed by Edward Carter Preston, struck in bronze and 4+3⁄4 inches (120 millimetres) in diameter, which shows Britannia with two dolphins behind her and a male lion in the foreground.

More than a million plaques were produced to commemorate the sacrifice of military and mercantile marine men and women who fell between 4 August 1914 and 30 April 1920.

We all desire that the brave and loyal service of the Mercantile Marine in war-time shall be gratefully recorded, and that the names of those who gave their lives for us shall be handed down with honour from one generation to another.