The most audacious attack was against the US fleet in Pearl Harbor but in the same period the Japanese invaded the Philippines, Thailand and British controlled Hong Kong and Malaya.Both the Americans and the British had underestimated Japan’s military and they paid the price. The British also suffered from their ongoing war against Germany and Italy. They had limited military resources and the choice had been made to concentrate these in Europe. Thus their forces in the Far East were equipped with outdated weapons. This is obvious in the case of the RAF, as shown by the following strength reports:
Source: AIR 22 ‘Air Ministry: Periodical Returns, Intelligence Summaries and Bulletins’The types available were second line aircraft like the Hawker Audax, Westland Wapiti, Westland Lysander, Vickers Vildebeest and a handful of relatively modern Curtiss P-36, Bristol Blenheim, Bristol Beaufort, Lockheed Hudson and Brewster F2A Buffalo.
These forces were not capable of standing up to the modern Japanese planes, especially the Mitsubishi A6M Zero.