Planning permission is not always required for the change of use of land or buildings.
The Use Classes Order identifies groups of similar land uses. Changes of use within the same use class can be carried out without submitting a planning application e.g. change of use from a butcher’s shop to a chemist’s shop.
Some changes from one use class to another and some temporary changes of use don't require permission e.g. change of use from a bank to a shop.
Certain uses don't fall within a particular use class because of their unique nature or because they comprise a mix of uses. Planning permission is likely to be required for any change to or from uses that don’t fall within a specific use class.
The planning portal gives detailed information about the Use Classes Order and changes of use not requiring planning permission.
if you require formal confirmation of the lawful use of a building or land you will need to apply for a Lawful Development Certificate.