This was to have major implications for the direction of the city's development. Up until the 1930s it had been a basic assumption of Birmingham's leaders that their role was to encourage the city's growth. Post-war national governments, however, saw Birmingham's accelerating economic success as a damaging influence on the stagnating economies of the North of England, Scotland and Wales, and saw its physical expansion as a threat to its surrounding areas – "from Westminster's point of view was too large, too prosperous, and had to be held in check". A series of measures, starting with the Distribution of Industry Act 1945, aimed to prevent industrial growth in the "Congested Areas" – essentially the booming cities of London and Birmingham – instead encouraging the dispersal of industry to the economically stagnant "Development Areas" in the north and west. The West Midlands Plan, commissioned by the Minister for Town and Country Planning from Patrick Abercrombie and Herbert Jackson in 1946, set Birmingham a target population for 1960 of 990,000, far less than its actual 1951 population of 1,113,000. This meant that 220,000 people would have to leave the city over the following 14 years, that some of the city's industries would have to be removed, and that new industries would need to be prevented from establishing themselves in the city. By 1957 the council had explicitly accepted that it was obliged "to restrain the growth of population and employment potential within the city".