National infrastructure assessment : analysis of options for infrastructure provision in Great Britain. Interim results by Tran, M, Hall, J, Hickford, A, Nicholls, R, Alderson, D, Barr, S, Baruah, P, Beavan, R, Birkin, M, Blainey, S, Byers, E, Chaudry, M, Curtis, T, Ebrahimy, R, Eyre, N, Hiteva, R, Jenkins, N, Jones, C, Kilsby, C, Leathard, A, Manning, L, Otto, A, Oughton, E, Powrie, W, Preston, J