By 1944, the threat of invasion to the United Kingdom had melted away. The balance of power had irrevocably changed. The Allies were now building up their forces in the United Kingdom in order to open up the second front as demanded by Josef STALIN.

The 21 Army Group was formed in 1943 to take under command all the operational formations dedicated to the forthcoming invasion of North West Europe. The formations not allocated to 21 Army Group were mainly training and reserve formations. General Headquarters Home Forces had migrated into the new 21 Army Group, so formations in the U.K. came under command of one of the existing Home Commands.