In the late 1950s, the telecommunications revolution was just getting started. The telephone network was expanding fast, and TV had recently expanded to two stations.
The country needed new infrastructure. The options were to lay thousands of miles of costly cables, or build a tower to transmit via microwave. The General Post Office decided on the latter.
And so, a transmission tower was designed for the centre of London. It would carry aerials for the Post Office’s microwave network, would be able to handle 150,000 simultaneous telephone connections, and would provide enough bandwidth for 40 channels of black and white or colour television.
Construction began in June 1961, and took four years at a cost of either £2.5m (if you believe Wikipedia) or £9m (if you believe BT).
At 189m (620 feet) high, it was Britain’s highest building, overtaking St Paul’s Cathedral. It would remain the country’s tallest until the 183m National Westminster Tower (now ‘Tower 42’) opened in 1980.
The Post Office (now BT) Tower was officially opened on 8 October 1965 by the prime minister, Harold Wilson – who made a telephone call to the Lord Mayor of Birmingham.
On 19 May 1966, the tower was opened to an eager public by Tony Benn, then the Postmaster General, and Billy Butlin, holiday camp tycoon (Butlin’s had taken the lease on the ‘Top of the Tower’, the 120-seat revolving restaurant on the 34th floor).
The price to get in to the tower was 4/- for adults and 2/- for children. With inflation, today that would be £4.30 and £2.15 respectively. Compare that to the Shard, which costs £24.95 for adults, and £18.95 for children, and it was a bargain.
In the first year, nearly one million people took the high-speed lifts to the top; 105,000 of them dined in the restaurant. An Act of Parliament meant that the tower was the only building in the country that it was legal to evacuate by lift in the event of a fire.
But the fun all came to an end in 1971. At 4.30AM, 31 October, a terrorist bomb exploded, causing extensive damage. The tower was closed to casual visitors soon after – by which time 4,632,822 people had ascended. The restaurant closed in 1980.
These days, the tower remains closed to the public, and is used by BT for corporate events. Its distinctive microwave transmitters were removed in 2011, but it is still used as a TV relay centre.