Percy Johnson-Marshall retained an interest in the continued redevelopment of Coventry long after he ceased to be a member of the City Architect's Department's staff in 1941. At some point he acquired a number of internal reports from the renamed Coventry City Architectural and Planning Department, where Arthur Ling was now the City Architect and Planning Officer.

He also collected a number of plans relating to the redevelopment of Coventry, produced by the same department, which both pre-dated and post-dated his period of employment there between 1938-1941.

This material was probably collected as background research for his book Rebuilding Cities ( 1966)