Lexicus
Deity
With the British blockade, eventually Europe is starved into submission. Whether Britain and the Soviets might come to some sort of negotiated agreement with Nazi Germany, I can't begin to guess.
The Soviet Union would never have come to a negotiated settlement with Nazi Germany, and I can't imagine Britain doing so either. The Germans came too close to gutting the USSR for Stalin to allow an independent Germany, and the British knew since the betrayal of the Munich agreement that making peace with Hitler would only give him a breathing space for further war.
The war would have taken longer without the US helping, but the end result would have been the same: Germany in ruins occupied by Allied troops. Almost certainly the demarcation between Soviet and Western allied occupation would be much further west without the US involved in the ETO.