Political map of South & Southwest Asia 15 February 1942 (Fall of Singapore): By February 1942 the Japanese forces invading Malaya had reached the perimeter of Singapore, Britain’s most important military base in Southeast Asia and the keystone of British defences in the region. Despite facing just 36,000 Japanese, the 85,000 troops in Singapore capitulated after only a week of fighting (Battle of Singapore) - a humiliating defeat and the largest surrender of British-led forces in history.