The University of Edinburgh/Nicolson Street Comprehensive Development Area (CDA) was mapped out by Percy Johnson-Marshall, Planning Consultant, in 1961-1962. All University building work in the central area was subject to this overall plan. Building projects and proposed developments within the CDA included, Bristo Square, George Square, Chambers Street, the Student Amenity, The Medical School Extension, the Physical Education Building, Old College and Buccleuch Place. As part of their work, the planning consultants acquired any material thought to be relevant, including plans for proposed University buildings, plans and alteration schemes for existing University buildings and copies of development plans by any other party pertaining to the Comprehensive Development Area.