This book is the first concise guide to the hidden world of underground London. Informative, authoritative & richly illustrated, this volume takes you on a subterranean tour of the many remarkable constructions that few even knew existed. Some of the installations were once highly secret, such as the government bunkers, civilian refuges, protected broadcasting studios & emergency control centres for public utilities. Other facilities described perform more mundane functions, including the mothballed Mail Rail (the Post Office Railway), telephone & power cable subways, electricity substations & sewage out-fall tunnels.