Photos: BT Tower at 40
London's landmark through the years - in pictures
![steve-ranger](https://www.zdnet.com/a/img/resize/b4917788016f51d5b397ccd99a6d348e4a5fdea1/2022/08/05/cfff1b63-6e97-4f64-b0ff-ffa2d16dc37b/steve-ranger.jpg?auto=webp&fit=crop&frame=1&height=192&width=192)
![40147736-1-1btbuild-custom.jpg](https://www.zdnet.com/a/img/resize/049a24a214f765f95c0c8abab09ec33f31175b7b/2014/08/29/bcec6c30-2f29-11e4-9e6a-00505685119a/40147736-1-1btbuild-custom.jpg?auto=webp&width=1280)
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London's landmark through the years - in pictures
The BT Tower, one of London's most famous landmarks, was opened by the then Prime Minister Harold Wilson 40 years ago on 8 October 1965.All photos: VisualMedia
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Originally known as the Post Office Tower, it was the UK's highest building at the time, standing 189 metres tall including a 12 metre London Weather Centre radar mast.
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The tower was designed to meet the increased demands of broadcasting by allowing the use of microwaves instead of landlines for transmitting television signals.
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Today the tower handles around 3,000 switched calls per day, 99 per cent of all live football and terrestrial television passes through it and it is a Grade II listed building.
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It cost £2.5m to build and can stand up to 23 centimetres shorter in winter than it is in summer - because of contraction and expansion - and is designed to sway no more than 20 centimetres each way in winds up to 100mph.
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