The romans had taken over
In 1942, Great Britain was at the head of the British Empire, the largest Empire in known history.
At it's peak, the empire consisted of nearly 25% of the world's population, a large landmass, unmatched resources and hundreds of millions of subjects.
If the axis were able to control Great Britain, they would quite possibly have complete hegemony over the world.
The American Revolution was principally caused by colonial opposition to British attempts to impose greater control over the colonies and to make them repay the crown for its defense of them during the French and Indian War (1754–63)
The answer is farming, fishing and shipbuilding. they also had to do weaving, shoe making, cabinetmaking, and other crafts were done also.