Evan, Britain certainly underestimated the Japanese too. In Burma (You can tell I'm reading a book about it, can't you?) the British, Indians and Ghurkas were constantly told to attack even when severely under-strength. Alexander seemed to think that the Japanese would cave in (or something) under pressure, it wasn't until 1942 that he realised Burma was lost and ordered the retreat (with Slim and Stilwell in agreement).
It was the same in Singapore and in the Indian Ocean. The British were thinking the IJN was nothing compared to the Royal Navy, how wrong they were.
Rebel, the British Empire wasn't just England. Canada, Australia, New Zealand, [Parts of] Africa, India, Burma, Hong Kong all were part of the British empire. And the biggest contributers (Canada and the ANZACs were not touched, except Darwin was bombed a few times).