Singapore represented the full influence of Britain in the East. Singapore was primarily a naval base but all three units of the military were based there. If Singapore fell to the Japanese it would be a huge psychological blow to British and Commonwealth forces based in the East and a huge boost to the Japanese military.
The spread of Japan’s military capability had been seen since the attack on Manchuria in 1931 and the full-scale invasion of China in 1937. It was only then that commanders in Malaya and Singapore started to question just how well the Malayan Peninsula was guarded.
In 1937, the GOC Malaya, Major-General W G S Dobbie, made a study of defences both in Singapore and Malaya as a whole. He reported back to London that an invasion was a possibility during the monsoon season (October to March); in fact, the Japanese might welcome the monsoon weather as it would make aerial reconnaissance very difficult and would act to disguise Japanese troop and shipping movements. Dobbie identified the areas where he believed an invasion force would land – Singora in southern Thailand and Kota Bharu in northeast Malaya. Dobbie clearly stated that the defence of Singapore rested on the British ability to defend Malaya and that reinforcements had to be sent to the area immediately. However, only one battalion was sent to Malaya and £60,000 given for defence works, most of which was spent in Johore to the north of Singapore.
In 1939, after war in Europe had broken out, the three service heads in Singapore sent a joint request to the Chiefs-of-Staff in London. They jointly informed London that in their considered opinion, air power in Singapore had to be greatly extended. They wanted 200 aircraft almost immediately but a desired total of 566 aircraft was asked for. They believed that with such a force, the army presence in Singapore could be reduced to 23 battalions and those men not required could be redeployed. They were told that 566 aircraft was excessive and that 336 aircraft should suffice, though these would take some time to deliver. The Chiefs-of Staff also stated their belief that the army in the region should be expanded and that a whole infantry division would be sent from India.
However, such a movement of army personnel did not have the support of Winston Churchill. He wrote to the Chiefs-of-Staff in January 1941:
“I do not remember to have given my approval to these very large diversions of force. On the contrary, if my minutes are collected they will be seen to have an opposite tendency. The political situation in the Far East does not seem to require, and the strength of our Air Force by no means warrants, the maintenance of such large forces in the Far East at this time."
Despite Churchill’s reservations, the 9th Indian Division (minus one brigade) arrived in Singapore in April1941. On August 7th, a new GOC Malaya arrived to take up his post – Lieutenant-General A E Percival. He informed the War Office in London that in his estimate Malaya needed six divisions to defend itself against a Japanese invasion.
Percival was also concerned about the training of the troops stationed at Singapore and Malaya. Many seemed to have their time taken up with the defence of air bases and very few, if any, had prepared for jungle warfare. However, commercial reasons explained the latter as the owners of the rubber plantations rarely, if ever, gave permission for training to take place on land they owned as it disrupted the production process.
Even as Singapore was under threat in January/February 1942, General Wavell commented to Percival that he could not understand why defence work in Johore Province, immediately to the north of Singapore, had not been undertaken. Nor could he identify any major defence work done on the northern side of the island. The only plan to defend Singapore seemed to be the destruction of the causeway that linked Singapore to the Malayan mainland. However, this was made difficult in the extreme by the simple fact that it was over 1000 metres long and 70 metres wide. It also proved to be of little value in defending Singapore itself.