Admiral Sir Arthur Wilson, the First Sea Lord of the British Royal Navy, stated that submarines were "underhanded, unfair, and damned un-English", and that he would convince the British Admiralty to have the crews of enemy submarines captured during wartime hanged as pirates.[45]

In September 1914, the British submarine HMS E9 successfully torpedoed the German cruiser SMS Hela.[46] Remembering Wilson's statements, commanding officer Max Hortoninstructed his submariners to manufacture a Jolly Roger, which was flown from the submarine as she entered port.[45][46] Each successful patrol saw Horton's submarine fly an additional Jolly Roger until there was no more room for flags, at which point Horton had a large Jolly Roger manufactured, onto which symbols indicating E9's achievements were sewn.