Most physical alterations or expansions to premises will need planning permission from the local authority planning department in the area where the work is being carried out. This permission must have been received before any change of use commences, or any building or development work is started.

The planning system in the UK is designed to balance the need for economic development with the protection of the local environment. When assessing applications, local authority planning departments consider issues such as compliance with their Local Plan (which sets out a framework for future development in their area), the design and appearance of the proposed development, environmental impacts, loss of privacy or light in neighbouring properties and traffic implications.

This factsheet explains when planning permission is required and the different types of permission that can be granted. It also explains what is meant by premises use classes.

Information about how to apply for planning permission and the factors that a local authority planning department will take into account when deciding whether to grant planning permission is provided in a separate factsheet, Applying for Planning Permission.