Did Britain underestimate Japan?

Did Britain simply underestimate Japanese military capability?

Not uniformly; many naval leaders understood Japanese competence, but Britain lacked enough modern ships and aircraft to act on that knowledge.

Some British factions held racist assumptions and the speed of Japan's historical advance still surprised planners. Many Royal Navy leaders, however, had served alongside Japan in the First World War or learned from liaison missions and therefore understood that the Japanese were capable opponents. Britain's active carriers and modern ships were already demanded by the Home Fleet and Mediterranean war. The central problem was insufficient modern force in theater, not universal ignorance of Japanese competence.