The modern-day planning system is a post-war invention, with roots that may be traced to the enactment of the Town and Country Planning Act 1947. The notion of 'planning' land use goes back further still, arguably as far back as ancient Greece when Piraeus was laid out following a 'grid-iron' street plan. Consistent throughout an examination of such urban history is that society affords a measure of regulatory control to the state (i.e. the government) to supervise the use of land. What best distinguishes the 1947 legislation is its scope, principally that it established a comprehensive and universal system of land use control.
Then, as now, the system served the key function of balancing public and private interests. The creation of the post-war planning system effectively 'nationalized' the right of private individuals to develop land by stipulating that planning permission would be required for certain types of development. In return these 'applicants' were afforded the automatic right of appeal (to a planning inspector or to the Deputy Prime Minister) should consent be refused. This newly created system of town and country planning would exist to secure the interests of the community, in cases where amenity would be harmed. Amenity itself was never defined and since 1947 to the present it has been interpreted (usually by virtue of legal interpretation in the Courts) in many ways.
The public interest would, therefore, take precedence over the private right to develop land and property (Grant 1992). Nevertheless, the private interest should not be unduly restricted and in a variety of circumstances various freedoms, such as the right to extend a dwelling within a certain volume, would be deemed to fall outside planning control. Today, such freedoms from the need for planning permission are granted by subordinate (i.e. laid before Parliament) legislation, such as contained in the General Permitted Development Order and Use Classes Order (which permit certain building works and changes of use without planning permission).
What has changed since 1947 are the policy outcomes that the system is designed to secure. In 1947 this meant post-war reconstruction. In the first decade of the twenty-first century, it means 'sustainable development', so that by way of example, government policy seeks (by 2008) that 60 per cent of new housing will be built on brown (i.e. previously developed) land or by conversion of existing stock.