A taskforce set up by Arup after the 11 September terrorist attacks, has questioned whether building techniques have taken account of the lessons learned from the World Trade Centre collapse.
The report, published by the firm's extreme events mitigation taskforce, states: "Further research is needed … to cover the performance of passive fire protection under impact and with structural deformations."

The report adds that building materials makers should be encouraged to test their products in hydrocarbon fires, and calls for further research into the use of polypropylene fibres in concrete.

The report notes that more work is required on how to evacuate people from tall buildings.

It suggests that phased evacuation might not be an adequate answer but rejects any idea of using dramatic escape methods, such as parachutes, abseils, chutes or other ad hoc external methods.

The taskforce calls for a linked up approach to evacuation. It says: "It is vital that there is a co-ordinated approach throughout the building, as inconsistent actions by some tenants can threaten the safety of the whole building."

It also suggests setting up a licensing regime for those in charge of tall buildings, along the lines of that applied to sports stadiums.