on the city occurred on the night of 29/30 December, and nightly raids ensued for over a week, accompanied by daylight raids from 12 January 1942. As the Japanese army advanced towards Singapore Island, the day and night raids increased in frequency and intensity, resulting in thousands of civilian casualties, up to the time of the British surrender. In December 51 Hawker Hurricane Mk II fighters were sent to Singapore, with 24 pilots, the nuclei of five squadrons. They arrived on 3 January 1942, by which stage the Buffalo squadrons had been overwhelmed. No. 232 Squadron RAF was formed and No. 488 Squadron RNZAF, a Buffalo squadron, had converted to Hurricanes; 232 Squadron became operational on 20 January and destroyed three Nakajima Ki-43 "Oscars" that day, for the loss of three Hurricanes. Like the Buffalos the Hurricanes began to suffer severe losses in dogfights. From 27 to 30 January, another 48 Hurricanes arrived on the aircraft carrier . Operated by the four squadrons of No. 226 Group RAF, they flew from an airfield code-named P1, near Palembang, Sumatra in the Dutch East Indies, while a flight was maintained in Singapore. Many of the Hurricanes were destroyed on the ground by air raids. The lack of an effective air early warning system throughout the campaign meant that many Commonwealth aircraft were lost in this manner during Japanese attacks against airfields. By the time of the invasion, only ten Hurricanes of 232 Squadron, based at RAF Kallang, remained to provide air cover for the Commonwealth forces on Singapore. The airfields at Tengah, Seletar and Sembawang were in range of Japanese artillery at Johor Bahru. RAF Kallang was the only operational airstrip left; the surviving squadrons and aircraft had withdrawn by January to reinforce the Dutch East Indies. On the morning of 9 February, dogfights took place over Sarimbun Beach and other western areas. In the first encounter, the last ten Hurricanes were scrambled from Kallang Airfield to intercept a Japanese formation of about 84 aircraft, flying from Johor to provide air cover for their invasion force. The Hurricanes shot down six Japanese aircraft and damaged 14 others for the loss of a Hurricane. Air battles went on for the rest of the day and by nightfall it was clear that with the few aircraft Percival had left, Kallang could no longer be used as a base. With his assent, the remaining flyable