The famous Telecom (now BT) Tower. The BT Tower is a grade II listed communications tower located in Fitzrovia, London. It has been previously known as the GPO Tower, the Post Office Tower, and the British Telecom Tower. The main structure is 177 metres with a further section of aerial rigging bringing the total height to 189 metres. Upon completion in 1964, it overtook the Millbank Tower to become the tallest structure in London until 1980, when it in turn was overtaken by the NatWest Tower.