Planning permission or planning consent is the permission required in the United Kingdom and Ireland in order to be allowed to build on land, or change the use of land or buildings. Within the UK the occupier of any land or building will need title to that land or building (i.e. "ownership"), but will also need "planning title" or planning permission. Planning title was granted for all pre-existing uses and buildings by the Town and Country Planning Act 1947, which came into effect on 1 July 1948. Since that date any new "development" has required planning permission. "Development" as defined by law consists of any building, engineering or mining operation, or the making of a material change of use in any land or building. Certain types of operation such as routine maintenance of an existing building are specifically excluded from the definition of development. Specified categories of minor or insignificant development are granted an automatic planning permission by law, and therefore do not require any application for planning permission. These categories are referred to as permitted development.