Anti - Invasion Exercise -- A large-scale anti-invasion exercise, in which over 50,000 troops, including armored divisions, were engaged, has recently taken place in the Southern command. The opposition was arranged to test most of the counter measures which will be employed in the vent of an attempted invasion. General Sir Alan Brooks, the commander-in-chief, home forces was present at the exercise. A mortar in action. August 8, 1941. (Photo by British Official Photograph).