If a development in the UK does not have planning permission, the planning authority has several rights and options available to them, including:
The planning authority can take enforcement action against a development that does not have planning permission. This may include issuing an enforcement notice, which requires the developer to stop the work or remove the development, and if the developer fails to comply, the authority can take further legal action.
The planning authority can ask for the demolition of a building that was built without planning permission.
The planning authority can impose fines or penalties on the developer for building without planning permission.
The planning authority can decide to grant retrospective planning permission for the development, however this is not guaranteed and it will depend on the specific circumstances of the case and the effect on the surrounding area.
The planning authority can serve a notice to the developer requiring them to provide information about the development and how it came about, this is known as a planning contravention notice.
The planning authority can also serve a Stop Notice which requires the developer to stop the works immediately.
It's important to note that, if the development has a significant impact on the surrounding area and the environment, the local planning authority has a duty to take enforcement action, regardless of whether the developer has applied for retrospective planning permission or not.