In the decades after World War I, Britain expanded Singapore Naval Base at Sembawang on Singapore's north coast as part of plans to deter Japanese expansionism in the region (the Singapore strategy). The resulting facility was among the most important in the British Empire and included the large King George VI graving dock and Admiralty No.IX floating dry dock. The Commonwealth forces allocated to Malaya and Singapore were swiftly defeated in the months after the outbreak of the Pacific War, however, and the island was surrendered to the Japanese on 15 February 1942. Singapore was bombed by Japanese aircraft on a number of occasions during the Battle of Malaya and subsequent fighting on the island itself; these raids caused many civilian deaths.