Percy Johnson-Marshall's files relating to the Administrative County of London Development Plan (1951) Review. Material includes the "Architect's Department Town Planning Division First Review Handbook", the 4th draft of the "Statement on proposals for alterations and additions". Other preparative material for the statement includes survey reports and statistics, proposed amendments to the Programme Map, reports for Committees and other Committee papers.

File of research materials kept by Percy Johnson-Marshall while employed in London County Council Architect's Department. The file contains papers and research notes on a number of planning methodologies including, daylight, building density, development in central London, child population statistics and planning controls.

In addition the file contains related typescript notes of visits, meetings and talks, memoranda on departmental procedures and notes on legislative change.