This austere structure is located in central Manchester between George St and St James St. I believe it to be an entrance to the Guardian Exchange. This underground communications bunker was built in the 1950s and was designed to withstand atomic attack on Manchester and preserve regional and national communications links. The development of the H bomb reputedly led to its security being compromised. The bunker and its tunnels are still used to route telecommunications cables under the city. A fire in such a tunnel in 2004 put parts of the telephone network out of action for several days.
