Holborn Tube Station's Hidden Nuclear Bunker London

Kingsway telephone exchange was a Cold War-era hardened telephone exchange underneath High Holborn in London. Initially built as a deep-level air-raid shelter in the early 1940s, it was instead used as a government communications centre. In 1949 the General Post Office (GPO) took over the building, and in 1956 it became the UK termination point for TAT-1, the first transatlantic telephone cable. Closure of the facility began in the 1980s. It was built together with underground exchanges in Birmingham and Manchester, and was originally covered by a D-Notice.