buffnut453
Captain
The Brits had a plan to occupy Thailand, but like Norway, they let the enemy get there first.
Because it was politically untenable. Implementing Op MATADOR would have greatly increased the probability of successfully defending the peninsula. It was not implemented because it involved, effectively, the invasion of a neutral country which would have gifted a propaganda coup to Tokyo.
There was a missed opportunity in late November 1941 to convince leadership in Bangkok of Japan's intentions. It would have necessitated one of the most daring PR missions of the entire war to identify occupation of certain airfields in FIC with IJAAF fighters. Photographic proof of Japanese fighters in proximity to the Thai coastline could have enabled a diplomatic agreement whereby Bangkok invited Malaya Command to help in the defense of Thailand. Unfortunately, no such mission was directed and the opportunity was missed.