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 event of an attempted invasion. General Sir Alan Brooke the commander-in chief, Home forces, was present at the exercise. During the exercise communication is maintained between units and headquarters by means of portable wireless telephoning sets. August 8, 1941. (Photo by British Official Photograph).