No the end of the British Empire was in WWI and General Allenby..
Not quite. Not until 1931, when the Brits dropped off the gold standard, did it become clear that the financial center of the world was never again going to be London. Lend lease put paid to all that, and the Brits became our mercenaries. They and the Russians. Without them we could not have fought both the Germans and the Japanese. Just imagine how differently things would have gone if the Germans had been able to invade England in 1940.