 Japanese troop convoys were first sighted on 6 December . Two days later , Japanese aircraft raided Singapore ; although the Prince of Wales 's anti @-@ aircraft batteries opened fire , they scored no hits and had no effect on the Japanese aircraft . A signal was received from the Admiralty in London ordering the British squadron to commence hostilities , and that evening , confident that a protective air umbrella would be provided by the RAF presence in the region , Admiral Phillips set sail . Force Z at this time comprised the battleship Prince of Wales , the battlecruiser Repulse , and the destroyers Electra , Express , Tenedos and HMAS Vampire . 
