However, this assuming the US doesn’t join in the war until the end of 1941, the British would of had 2 years of standing alone against the British.
The US were already helping the British even before they entered the war in the form of lend-lease, destroyers for bases, and convoy protection.
The British couldn’t take any Offensive action against the Germans.
At that point in the war, the British had to stay defensive…
This cuts Britiain off from most outside aid (Canada is still there, but would that of been enough?). In addition, it decreases the amount of manpower flowing into Britain from the Commonwealth.
The original plan called for only 166,000 Germans, the Britiain defense units probably could of held that number off.
Germany would of bought itself a lot of time. It would have time to develope it’s Nuclear program, Airforce (Jet Engines), Tank design, and yes, it’s Navy.
Then the invasion would have to be placed on hold from its original date of 1940…
Even if Britain hadn’t fallen to invasion, the war would of dragged on for many, many years. Almost all of Southern Britain would of been utterly destroyed by bombing.
The Germans had already loss huge numbers of bombers to the RAF, they couldn’t keep it up much longer.