Guardian telephone exchange

Guardian Exchange was an underground telephone exchange built in Manchester from 1954 to 1957. It was built together with the Anchor exchange in Birmingham and the Kingsway exchange in London – all believed to provide hardened communications in the event of nuclear war; as well as linking the UK government in London to the US Government in Washington, D.C. by means of a secure and hardened transatlantic telephone cable making landfall near Oban and running through Glasgow, Manchester and Birmingham. Today, the underground site is used for telephone cabling. Constructed at a depth of below 35 metres (115 ft), the tunnels are about 2 metres (80 in) in diameter. The exchange cost around £4 million (approximately £126 million in 2015 prices), part of which was funded by the United Kingdom's NATO partners.