While steaming back to Alexandria along with Vian's force, destroyer HMS Jervis reported an apparently successful depth-charge attack on an unidentified submarine.[11] The only axis submarine off Alexandria was the Italian Sciré, which was carrying a group of six Italian frogmen commandos, including Luigi Durand De La Penne, equipped with manned torpedoes. Shortly after Vian's force arrived in Alexandria, on the night of 18 December, the Italians penetrated the harbour and attacked the fleet.