The ODPM said in a statement this week that steps had been taken to prepare for a possible attack. The statement said: "A great deal of planning has taken place since the attacks in the USA on 11 September. This work has covered a wide range of scenarios including plans for the clearance, removal and disposal of debris post-catastrophic incident in the capital."
The statement added: "These plans have been drawn up with the assistance of a working group that draws upon experts in the private sector as well as those in government departments and agencies, emergency services and local government."
Sources close to London Resilience, which is chaired by former construction minister Nick Raynsford, say 20 of the UK's biggest structural engineering firms are on the list.
Hundreds of structural engineers in New York, including employees of firms such as Arup and Buro Happold, volunteered to help out in assessing building work after the World Trade Centre terrorist attacks.