Blazing furniture made towers collapse

An inferno of office furniture, paper and fittings caused the Twin Towers to collapse, not the burning fuel of the aircraft that hit them.

Dr John Roberts of the Babtie engineering group told the British Association Science Festival at Leicester University: "It now appears from US investigative teams that the fuel burnt out very rapidly.

"The real fire damage came from the widespread combustion of the contents of the buildings." The investigators found there was extensive damage to about three storeys of each tower, in which the impact of the aircraft - each weighing more than 100 tonnes and travelling at nearly 500mph - destroyed at least two thirds of all the steel supports on the side they hit.

But despite the loss, the steel frame of each tower was able to continue carrying its load. It was only when the fires took hold that the frame began to weaken.