Maplin (Foulness) - planning London's third airport : report of the proceedings of a one-day symposium held on 2nd February 1972 at the North East London Polytechnic, Waltham Forest Precinct, and organised by the Department of Civil Engineering / head of department J.R. Slaney; symposium organiser Denis Smith. report of the proceedings of a one-day symposium held on 2nd February 1972 at the North East London Polytechnic, Waltham Forest Precinct, and organised by the Department of Civil Engineering /