Which British Prime Minister officially opened what was then called the Post Office Tower?

The BT Tower is a communications tower located in Fitzrovia, London, owned by BT Group. It has been previously known as the GPO Tower, the Post Office Tower and the Telecom Tower. The main structure is 177 metres (581 ft) high, with a further section of aerial rigging bringing the total height to 191 metres (627 ft).

The tower was topped out on 15 July 1964 and officially opened by the then Prime Minister Harold Wilson on 8 October 1965. James Harold Wilson, Baron Wilson of Rievaulx, (11 March 1916 – 24 May 1995) was a British Labour Party politician who served as the Prime Minister of the United Kingdom from 1964 to 1970 and 1974 to 1976.

The tower was designed by the architects of the Ministry of Public Building and Works: the chief architects were Eric Bedford and G. R. Yeats. Typical for its time, the building is concrete clad in glass. The narrow cylindrical shape was chosen because of the requirements of the communications aerials: the building will shift no more than 25 centimetres (10 in) in wind speeds of up to 150 km/h (95 mph).