This article from British Airways News, 10 March 2005:

Heathrow’s new air traffic control tower has just completed the intricate process of being raised to its full height of 87 metres, dominating the airport skyline. The tower began construction near Terminal 4 and then all 900 tonnes of it were moved lock, stock and barrel 2kms across the airfield to its final site next to Terminal 3.

Since January six steel mast sections have been slotted under the cab of the tower to raise it to its full height, more than double the height of the existing control tower.

Designed by the Richard Rogers Partnership, the £50m air traffic control tower will feature the latest technology and offer Heathrow’s controllers a 360- degree field of vision – the best viewing capability of any control tower in the world – when it becomes operational in 2006.