That tower
The new tower needs to be 87metres tall for the occupants to see fins over the roof of T5 and the double height piers for the A380.
In the summer, the base building will appear.
The cables will take 160t force (1/10th load) to help reduce vibration in the wind - also there are spoilers on the mast and also active mass dampers made in Japan.
The design (by Arup) even allowed BAA to keep stands and taxiways open (work out the reason yourself...).
Whilst being assembled, the temporary stay cables had to extend and contract as the tower went up and down.
Details shamefully nicked from the 24th Feb 2005 edition of the mag called New Civil Engineer