An interesting but not well known fact is that British troops were sent to Saigon in 1945 to take the surrender of the Japanese troops.
https://en.m.wikipedia.org/wiki/War_...1945–46)
They fought a six-month war against the Viet Minh before handing over to the French, who had finally got themselves organized.
British troops were also employed in a similar way in Indonesia. Dirk Bogarde wrote a very good novel called “A Gentle Occupation” based on his Army experience there.