The Drill Hall was the headquarters of the Wimbledon Local Defence Volunteers, later known as the Home Guard. Formed in May nineteen forty, its main duty was to prepare the country for invasion and “to meet any military emergency until trained troops could be brought up". The force comprised men who were too old or too young to serve in the armed forces, or those working in reserved occupations.
Recruits manned defensive posts, guarded vulnerable sites and staged night patrols watching for enemy gliders or parachute landings. Initially a rag-tag militia with make-do uniforms and weapons, the Home Guard evolved into a well-trained and well-equipped force.
The local branch, the fifty-fourth (Wimbledon) Home Guard, had one thousand five hundred recruits within a year of its formation. It was one of twelve Surrey battalions attached to the East Surrey Regiment, a regular army unit. The regiment worked closely with the volunteers. Officers gave lectures and platoons gave training demonstrations. Army units also participated in Home Guard exercises, sometimes adopting the role of an enemy attack force.