Originally Posted by LeEnfield
We had more than that when we put our Armies into Europe.
I think LeEnfield is correct. The largest British only land battle in WWII was likely Brits vs. Germans in and around the Belgian border in May 1940 - which of course lead to Dunkirk and that's probably why it isn't a number bandied about. Better to remember the men who were saved at Dunkirk rather than the total amount of men who had been fielded. Too easy to see then the amount lost. Not a favorable thing in wartime and now as years have passed still not a thing popular to remember.
"Do not forget your dogs of war, your big guns, which are the most-to-be respected arguments of the rights of kings."
- Frederick the Great, King of Prussia