By submarinesThe personnel of the British submarineHMS Utmost showing off their Jolly Roger in February 1942. The markings on the flag indicate the boat's achievements: nine ships torpedoed (including one warship), eight 'cloak and dagger' operations, one target destroyed by gunfire, and one at-sea rescue
Following the introduction of submarines in several navies, Admiral Sir Arthur Wilson, the First Sea Lord of the British Royal Navy, stated that submarines were "underhand, unfair, and damned un-English", and that he would convince the British Admiralty to have the crews of enemy submarines captured during wartime be hanged as pirates.
In September 1914, the British submarine HMS E9 successfully torpedoed the German criuser SMS Hela. Remembering Wilson's statements, commanding officer Max Horton instructed his sailors to manufacture a Jolly Roger, which was flown from the submarine as she entered port. Each successful patrol saw Horton's submarine fly an additional Jolly Roger until there was no more room for flags, at which point Horton then had a large Jolly Roger manufactured, onto which symbols indicating E9's achievements were sewn. A small number of other submarines adopted the practice:HMS E12 flew a red flag with the skull and crossbones on return from a foray into the Dardanelles in June 1915, and the first known photograph of the practice was taken in July 1916 aboard HMS H5.
The practice restarted during World War II. In October 1941, following a successful patrol by HMS Osiris, during which she sank the Italian destroyer Palestrothe submarine returned to Alexandria, but was ordered to remain outside the boom net until the motorboat assigned to the leader of the 1st Submarine Flotillahad come alongside. The flotilla leader wanted to recognise the boat's achievement, so had a Jolly Roger made and delivered to Osiris.(I) After this, the commanders of submarine flotillas began to hand out the flags to successful submarines. Although some sources claim that all British submarines used the flag, the practice was not taken up by those submarine commanders who saw it as boastful and potentially inaccurate, as sinkings could not always be confirmed. During the war, British submarines were entitled to fly the Jolly Roger on the day of their return from a successful patrol: it would be hoisted as the boat passed the boom net, and remain raised until sunset.