There are several different forms of enforcement action that a Local Planning Authority (LPA) can take. The most common are:
A temporary stop notice which comes into force straight away and stops any further development for 28 days. If you fail to comply, it is an offence with the possibility of an unlimited fine being imposed.
An enforcement notice to stop development. You would have the right of appeal to the Planning Inspectorate against this sort of notice but there is a time limit of as little as 28 days to make this appeal and a fee would need to be paid in some instances. There is an ability to get planning permission by appealing this notice is some circumstances.
A stop notice which can only be issued at the same time as an enforcement notice and is used to stop the development before the enforcement notice comes into effect. If you don’t stop work, it is an offence with the possibility of an unlimited fine being imposed.
An injunction is an application to the courts to stop the development (this could be the removal of caravans or the stopping of work). Failure to comply with an injunction can result in a prison sentence or fine. If you receive an injunction you will need to get the advice of a solicitor urgently. Challenging injunctions in the courts is very expensive.