WWII starts just as in the original timeline and France still falls.
However, only the British Empire (no USA, no Soviet Union) opposes the Axis. However, all subjects and citizens of the Empire whether or not in a settler colony are 100 percent loyal to the British Empire, really want and need Britain to win and there are no independence movements whatsoever. In this timeline, Britain can try to literally arm up all of India, all of its African colonies etc with no political considerations whatsoever for dealing with insurrections after. In other words, this is Britain that can and will fight at full power.
Can this British Empire singlehanded win WWII?
Or do they lose? Keep in mind that the Empire can literally summon and arm troops from 1/4 of the entire world and India alone has more population than the whole Axis combined (I think).
Assume that there are no nuclear weapons.