Britain's position in 1940 was often described as 'alone' and 'weak'. Yet the reality was very different. Not only did Britain have powerful navy and RAF forces, but these forces were backed up by the nation's Home Guard – thousands of men and women in secret roles ready to help fight against invasion. Historian Andrew Chatterton shares some of the incredible stories of derring-do.

Andrew Chatterton is a Second World War historian. His main area of interest is the highly secret civilian forces set up to hamper a German invasion of Britain. He is author of Britain’s Secret Defences: Civilian Saboteurs, Spies and Assassins During the Second World War.