The practice restarted during World War II. In October 1941, following a successful patrol by HMS Osiris, during which she sank the Italian destroyer Palestro, the submarine returned to Alexandria, but was ordered to remain outside the boom net until the motorboat assigned to the leader of the 1st Submarine Flotilla had 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.