The Sime Road location had to be abandoned during the Battle of Kranji, with Lieutenant-General Percival shifting the Combined Operations Headquarters to Fort Canning Bunker on 11 February 1942. By the latter stages of the battle for Singapore, the Japanese were bombing the Central Area of Singapore, including Fort Canning Hill, at will. Fort Canning Hill was also within range of the Japanese artillery, forcing personnel into the bunker. There were around 500 officers and men in the bunker in the latter stages of the battle.