HMS Petard was a P-class destroyer of the British Royal Navy that saw service during the Second World War. She was one of only three P-class ships, out of the original eight, to survive the war in a serviceable condition.Originally to have been named HMS Persistent, Petard was launched in March 1941. She initially carried the pennant number G56, which was changed after the war to F56.

Petard had the distinction of sinking a submarine from each of the three Axis navies: the German U-559, the Italian Uarsciek and the Japanese I-27.Members of the ship's crew recovered from U-559 a new, four-wheel Enigma cypher machine and the books to go with it, albeit at the cost of the lives of her First Lieutenant and an Able Seaman, both of whom were drowned when the U-boat they were searching sank with them inside.

Lieutenant Francis Anthony Blair Fasson, (17 July 1913 – 30 October 1942), known as Tony Fasson, was a Royal Navy officer. He was posthumously awarded the George Cross "for outstanding bravery and steadfast devotion to duty in the face of danger" when on 30 October 1942 in action in the Mediterranean Sea he captured codebooks vital for the breaking of the German naval "Shark" Enigma cipher from the sinking German submarine U-559.