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, part of which was funded by the United Kingdom's NATO partners.

Anchor Exchange was an underground, hardened telephone exchange built in Birmingham, England. Construction commenced in 1953 under the guise of building an underground railway. It opened in September 1957 at a cost of £4 million. It was located nominally on Newhall Street. However its network of tunnels extended from at least the Jewellery Quarter to Southside.