And also, Germany was far from getting the bomb in 1945, but I think they most certainly would have had it by 1950.

Secondly, I think if the Germans were in London after a successful invasion they could have negotiated a treaty with England. You said that England wouldn't agree to peace according to Churchill. Well, Churchill wasn't exactly the most unbiased man on the subject. If HE was in power, that is very true, but on the other hand, if the Germans pulled off the invasion, he wouldn't be in power. I think England would have accepted an equitable peace, which Hitler might have offered.
B)The British - not just Churchill - would have fought for every inch of land with every available weapon. There were even plans to dump oil into the Channel and light it on fire. They would not have surrendered.
What if the Sealion invasion had FAILED? What if all 30+ divisions were wiped out by combined land and sea attack?
No Barbarossa might have led to increased German activity in Africa, possibly even an assault on Malta, which would have been disastrous for the British.
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