Below the streets of Chancery Lane underground station are more than a mile long network of tunnels, and they are up for sale. They were originally dug in 1942 as a bomb shelter for 8,000 people during World War II but were then taken over by military authorities as a communications and intelligence centre. The site is known as the Kingsway Tunnels, and after the war they became a place to store historic documents. The Post Office later took over the property as a more secure location for its long distance phone exchange. Its last owner - was British Telecom when telephony was split from the Post Office. The tunnels are the size of 14 football pitches and include old engine rooms, a former canteen and a bar.