Recognising that Thailand & French Indochina essentially represent the front door to their Malayan stronghold the British enact a more proactive defence and instigate an Operation Menace type endeavour in French Indochina in late 1940.
With the Free French firmly installed in Indochina does this forestall the Japanese designs on Malaya?
I don't know much about Laos and Cambodian history. However, as a Vietnamese, I can point out a few things:
- When Japanese invaded Viet Nam in 1940, there was little resistance from France (part of the reason is that their government had allied with Nazi Germany). Hence, the Brit may not have any help from local French. Unless they are able to bring "Free France Army" [and most of them were in Africa as I remember], they'd suffer great casualties
- It wasn't until mid-1941 when the most effective anti-Jap and anti-French alliance/group was formed. Hence, I doubt there would be any real help as "insider"
- In addition, Laos and Northern Viet Nam are mostly mountainous area, this will limit armor as well as air force. While Cambodia and Southern Viet Nam have relatively large flat land, Japanese strongholds can be tough targets (this area yield a lot of crops)
So, any idea?