By the summer of 1940 nearly a million and a half British men had joined the Local Defence Volunteers (LDV), a response to the very real threat of invasion by a rapidly advancing German Army. This book explores the LDV’s transformation from an enthusiastic yet ill-equipped organisation into the capable Home Guard, which, as the threat of invasion receded, nevertheless became key to the UK’s local defence strategy, as well as a means of combating the purported Fifth Column.