The 1940 report of the Royal Commission on the Distribution of the Industrial Population, chaired by Sir Montague Barlow, examined the concentration of industry and population in Britain's large conurbations, especially London. It recommended restraining further metropolitan sprawl, dispersing industry and population to new and expanded towns, and coordinating this through national-level planning machinery. Its analysis fed directly into wartime reconstruction policy. It helped justify London's later statutory green belt and the New Towns programme.
The report made urban containment and planned decentralisation matters of official national policy in Britain. Its logic underpinned the green belt, the 1946 New Towns Act and the postwar planning system's commitment to limiting outward metropolitan growth.