Reasons for the fall of Singapore and Malaya to the Japanese

Good Japanese preparations

The Japanese had setup intelligence services in Malaya and Singapore to provide information on British defences and readiness

Japanese had owned land in Singapore and Malaya , many Japanese had operated studios here. took pictures of defences and roads

they also had operated incognito

They had signed a 'Treaty of Alliance ' with Thailand , which allowed them to land in southern Thailand

Superior Japanese forces

British had underestimated the Japanese

Japanese had a large , modern airforce and naval fleet.

'Zero' fighter planes had destroyed half of the British planes, which were old and outdated.

Better trained in jungle warfare

Better tactics

use of bicycles as a means of swift transport in Malaya instead of tanks

British priority to war in Europe

Germany was causing a lot of problems in Europe

Threatened to invade and conquer England

British more concerned in defending and making safe their homeland

Malaya and Singapore were not as important as they were only colonies

British had resource constrains, such as war supplies and soldiers thus they would rather focus on war in Europe