The BT Tower is a communications tower located in Fitzrovia, London, United Kingdom owned by BT Group. It has been previously known as the Post Office Tower, the London Telecom Tower and the British Telecom Tower. The main structure is 177 metres (581 ft) tall, with a further section of aerial rigging bringing the total height to 189 metres (620 ft). It should not be confused with the BT Centre (the global headquarters of BT). Its Post Office code was YTOW.

en.wikipedia.org/wiki/BT_Tower