Island Fortress: The Defence of Great Britain, 1603-1945 by Norman Longmate
Written by the author of The Real Dad's Army, Air Raid, The Bombers, The Doodlebugs and If Britain had Fallen, this second volume completes the account of the defence of Britain and particularly of England against invasion. It covers the threats to Britain from the period after the Armada to the fall of Hitler, covering such topics as Jacobite invasion and a 19th century Channel tunnel.