LONDON One of the UK’s most famous landmarks, BT Tower, was opened 40 years ago by the then Prime Minister Harold Wilson. Originally known as the Post Office Tower, it was Britain’s highest building, standing at 189 metres (620ft), including a 12 metre (40ft) London Weather Centre radar mast, and was visited by one million visitors in its first year of opening.
Widely acclaimed, and still one of London’s most famous landmarks, its key function was to help meet the increased demands of broadcasting, enabling the use of microwaves instead of traditional landlines for transmitting television signals. It was also famous for its revolutionary 34th floor, ‘Top of the Tower’ revolving restaurant.
Today the Tower remains an important part of the BT network, handling around 3,000 switched calls a day; 99 per cent of all live football and terrestrial television passes through BT Tower.
BT Tower is a Grade II listed building and was declared a national monument by English Heritage in 2001. It is part of BT’s Heritage Programme which preserves the UK’s rich telecommunications history.
Heat and cold cause the structure to expand and contract. BT Tower can be as much as 23 centimeters shorter in the winter than it is in the summer.
Construction of the tower cost £2.5 million and there are 13,000 tons of concrete in the Tower and it was designed to sway no more than 20 centimetres each way in winds up to 100mph.
Whilst access to the Tower is closed to the public, you can take virtual view from the top of the Tower at an online museum showing how communication has shaped the world.