The last time it fully opened its door to the public Margaret Thatcher was Prime Minister, the world was mourning the shooting of John Lennon, leg warmers were de rigeur and a pint of beer was just 35p. Unfortunately security concerns put the Kibosh on it.
Construction on the tower was completed on July 15, 1964, and the £9 million building was originally named the Post Office 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). When it was built it became the tallest builing in London and remained so until 1980, when it in turn was overtaken by the NatWest Tower.
Entry to the building is by two high-speed lifts which travel at 7 metres per second (15.7 mph), reaching the top of the building in under 30 seconds. An Act of Parliament was passed to vary fire regulations, allowing the building to be evacuated by using the lifts – unlike other buildings of the time. The tower is being used in a study to help monitor air quality in the capital. The aim is to measure pollutant levels above ground level to determine their source. One area of investigation is the long-range transport of fine particles from outside the city. There are more interesting facts about the tower in this Wikipedia article