The Battle Box The Battle Box is the popular name of the underground command centre constructed under Fort Canning , Singapore as an emergency , bomb - proof command centre during the Malayan campaign and the Battle of Singapore . The Battle Box is now a museum and tourist attraction . History . Given its position in the western Pacific , Singapore had long been recognised as being strategically important for the Royal Navy in order to counter the growing influence of the Japanese , who were regarded as being the logical threat to Britain ’ s interests in the Far East and the Pacific . To counter this , the Admiralty devised the Singapore strategy , which required a well equipped naval base . Accordingly , the Singapore Naval Base was constructed on the north shore of Singapore Island . The base , and its associated defences , required a large British military presence on the island . Fort Canning was used by the British army as their headquarters in Singapore , with a number of buildings built for this purpose in the 1920s . However , the lack of a headquarters combining all three services present in Singapore - the Army , Royal Navy and Royal Air Force - was appreciated in 1936 by the then Colonel Arthur Percival , the Chief of Staff to General Dobbie , ' General Officer Commanding , Malaya ' . To remedy this , a Combined Operations Headquarters was proposed for Fort Canning . Construction . Fort Canning is actually a small hill in the Central Area of Singapore Island . 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 . However , by the turn of the century , the construction of other defences around Singapore rendered the Fort Canning fortifications surplus to requirements . Located nearly 30 feet beneath the hill , the Battle Box complex was constructed as an emergency bunker for the Combined Operations Headquarters . Sources vary as to the number of rooms in the bunker ; one states 22 , while another , authored by the journalist who rediscovered the Battle Box , claims 29 rooms . The bunker was constructed with one metre thick ( 3 feet ) reinforced concrete walls to withstand direct hits from bombs and shells . The complex included a telephone exchange connected to all military and most civilian switchboards in Malaya , various signals and operations rooms , sleeping quarters and latrines . The Battle Box also included a cipher room for coding and decoding messages , but by the time of the fall of Malaya , this work had been shifted elsewhere and the cipher room was used as sleeping quarters . The Commander of Fixed Defences , Brigadier Curtis , co - ordinated the coastal artillery strikes on naval targets from the Battle Box . World War Two . By 1941 , the Battle Box was considered to be too small for its intended use . Percival , having returned to Malaya as a Lieutenant General and ' General Officer Commanding , Malaya ' , authorised construction of a new Combined Operations Headquarters at the Royal Air Force headquarters in Sime Road . The construction of this new headquarters began in 1941 , and was finished in December of that year . Although Combined Operations Headquarters had been relocated to Sime Road , the Battle Box remained the Headquarters of Major General Frank Keith Simmons , who as the ' Fortress Commander , Singapore ' , was responsible for the defence of Singapore Island . The Anti - Aircraft Gun Operations Room and Naval Extended Defences offices also remained at the Battle Box . The Japanese invaded Malaya on 8 December 1941 by moving south through Siam ( now known as Thailand ) , as well as by making landings at Kota Baharu , on the north east coast of Malaya . Rapidly retreating through Malaya , Allied forces were forced back to Singapore Island by 31 January 1942 . On 8 February , Japanese troops then crossed the Straits of Johor in a successful landing on the north west coast of Singapore Island , followed by a second landing near the Kranji River . The Sime Road location had to be abandoned during the Battle of Kranji , with Percival shifting the Combined Operations Headquarters to Fort Canning 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 , at will . Fort Canning was also within range of the Japanese artillery , forcing personnel into the Battle Box . There were around 500 officers and men in the Battle Box in the latter stages of the battle . The decision to surrender Singapore was made by Percival in a meeting on the morning of February 15 , 1942 . Held in the ' Commander , Anti - Aircraft Defence Room ' of the Battle Box , 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 Battle Box was later occupied by Japanese forces during the Japanese Occupation of Singapore . and it was used for communications right up to the time of the Japanese surrender . At the conclusion of the Second World War , the Battle Box complex itself appears to have been looted in the aftermath of the Japanese surrender ( upon re - entry to the complex in 1988 , evidence of a number of excavations were observed , presumably attempts to find loot that may have been concealed by the Japanese ) . Present day . After the war , Fort Canning was again used by the British as the Singapore Base District Headquarters . The British handed over Fort Canning to the Singapore Armed Forces in 1968 - 1969 , and the buildings of Fort Canning served for a time as the Singapore Command and Staff College . The Battle Box , having remained empty and unused since the war , was sealed off in the late 1960s due to safety concerns and its exact location forgotten . The Battle Box 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 . The Battle Box was developed into a museum , depicting the final days of the battle of Singapore . The museum was formally opened on 15 February 1997 , on the fifty - fifth anniversary of the surrender of Singapore .