Funny how things worked out. Britain was on the verge of being forced to sue for a negotiated peace after France fell and 300,000 British soldiers were on the verge of capture at Dunkirk. For whatever reason Hitler stopped the German army offensive and they eventually escaped to England. If they had been forced to surrender, England would have ceased hostilities. The rest is history. Dunkirk was the turning point of WW II.
Had a friend tell me it wouldn’t have mattered. USSR would have defeated Hitler. I pointed out that if England fell the entirety of Nazi power would fall on Russia. No need to maintain any forces. Land or air in the West. No England, no US entry. No 15 000 aircraft. 8,000 tanks,3,500 locomotives, 750 000 transport vehicles, no 100 octane aviation gas. Remarkably he was unimpressed. Said Stalin had it figured out.
OKW was also concerned that the supply lines and flanks were vulnerable and Hitler really thought he could negotiate with the British and perhaps even swing them over to unite against the Soviet Union. And Fatso Goering didn't help matters boasting that his Luftwaffe alone could finish off the BEF.
Dunkirk was the turning point of WW II.
By June 1940, the British Army stood at 1.65 million strong. Although it would have sucked to have lost 300,000 men as POWs or KIA, Britain would have gotten along.