I did a check on the figures. There are differences in figures depending on the source. The 3 : 1 ratio was probably due to Yamashita's boast that with 30,000 troops he defeated British force of 90,000. According to encyclopedia.com, the IJA had an establishment strength of 60,000 at the start of battle but under strength by about one-third (it was because of this that the Japanese had to call the bluff) against a British force of 88,600. This force comprised not only British, but also Australian, Indian and Malayan forces. Also the British had only 150 aircraft compared to the enemy's 600. The Japanese also had 80 tanks and 40 other armoured vehicle, a more complete fighting force. The Brits had no tanks. At the point of surrender, the IJA had gone up to 70,000 with the British force reaching 140,000 with 125,000 involved in the surrender. Despite the disparity in the forces, the vastly superior supporting elements of the Japs caused most analysts then to consider the fall of Singapore as inevitable.