If building works have already been carried out on the property without the required permission, we may ask you to make a retrospective planning application.
You apply in the same way as if you were applying before you carried out the work.
What if permission is refused?
If the decision is made that permission should not be granted you may be required to put things back as they were at your own expense.
Therefore if you have just started the work it is advisable to get permission as soon as possible before too much work is done.
There is also an appeals process (external link) if you feel the refusal is unfair.