This is the previously untold story of Britain's underground headquarters and factories. Born out of the growing threat from the air in the First World War, the quest for survivability developed to meet Hitler's Blitzkreig and this intensified during the Cold War nuclear era. Of the many sites described, the huge Corsham complex was arguably the most significant. This is the story of engineering achievement and bureaucratic bungling and even the most informed reader will learn something new. Reprint