Stamford Raffles had built a residence there in 1823, but when the Straits Settlement, which included Singapore, became a crown colony in 1867, a fort was constructed on the hill.

[3] The bunker was constructed with one metre thick (3 feet) reinforced concrete walls to withstand direct hits from bombs and shells.

[7] The complex included a telephone exchange connected to all military and most civilian switchboards in Malaya,[8] various signals and operations rooms, sleeping quarters and latrines.

[9] The Commander of Fixed Defences, Brigadier Curtis, co-ordinated the coastal artillery strikes on naval targets from the bunker.

The Sime Road location had to be abandoned during the Battle of Kranji,[15] with Lieutenant-General Percival shifting the Combined Operations Headquarters to Fort Canning Bunker on 11 February 1942.

Held in the 'Commander, Anti-Aircraft Defence Room' of the bunker,[18] a number of senior officers were in attendance, including Generals Bennett, Heath and Simmons.

With diminishing water supplies, and no viable options for launching a counterattack, the decision was made to seek terms with the Japanese.

The Fort Canning Bunker, having remained empty and unused since the war, was sealed off in the late 1960s due to safety concerns[22] and its exact location forgotten.

It was brought back into the public eye when it was "rediscovered" by a journalist in 1988, who was following a number of leads claiming the existence of an underground bunker complex on Fort Canning Hill.