Under the Town and Country Planning Act (1947) Comprehensive Development Areas (CDAs), proposed by a local authority and approved by the Secretary of State, allowed land and property to be acquired, for broad planning purposes, using compulsory purchase orders, if necessary. The Administrative County of London Development Plan, (1951) , identified 100 areas in need of comprehensive development but it was only feasible to designate eight CDAs: City of London, Stepney / Poplar, Bermondsey, South Bank, Elephant and Castle, Bunhill Fields, Lewisham Clock Tower and Woolwich.

The Reconstruction Areas Group (RAG), with Percy Johnson-Marshall as senior planner, was set up within the Planning Division of the London County Council's Architects Department to administer the CDAs, in 1949. Work continued in some CDAs after the Planning Division was reorganised in 1956, with Percy Johnson-Marshall overseeing those which fell within the jurisdiction of the North East Group.