Was the American force of the AEF the largest Army ever assembled in the UK?

Factual Questions
1

I was curious about whether or not it is possible that the American forces deployed to the United Kingdom during WW2 actually constituted the largest army ever present on Great Britain.

Facts I have dredged up:

Peak Size of American Forces in the UK (almost all in the south of England): 1.5 million May, 1944
Peak Size of British Army in WW2, 1945 - 2.9 million, 2.5 million in May, 1944

The question would then really be, did the total size of British forces in the home island ever get as big as the U.S. 1.5 million force in May 1944. I know that some British forces prior to the invasion of Normandy would have been in North Africa, Italy, and a number of other places.

2

There were 3.8 million men in the British Army by the end of World War I. It’s possible there could have been as many as 1.5 million in uniform on English soil being mustered out after the Armistice.

3

Really depends if you consider “Home Guard” Army or not since in both World Wars they were all activated at various points for defensive purposes.

4

That’s interesting—I had never thought WW1 British Army was a higher peak size than WW2, but I suppose it actually makes sense due to the really large troop deployments needed to man the lines of the Western Front. I would certainly expect a huge % of them were deployed to Europe though, but would more than 1.5m have been on British soil at any given time? Seems like…maybe, would be interesting to find out.

5

I’d suggest for any country on the winning side of a war, the moment they’d have the largest military headcount on their home soil is just after hostilities have ended and the mass demobilization is going on. As @Kent_Clark mentioned a bit earlier but might not have been noticed.

For the OP’s question, it’s unclear if that situation really counts for whatever was his underlying purpose in asking.