What is planning permission?
Planning Permission is the approval needed to carry out certain building works on your property. Planning Permission is required all over the UK and must be obtained before you can build a new structure, modify an existing structure or use a land or building for a different purpose from that for which it has already been approved.
Not every building project requires planning permission so it is your duty to find out if the project you have in mind requires planning permission. For example, loft conversion does not require planning permission anywhere in the UK as long as you meet certain conditions. These conditions can be found on the website of your local planning authority or gotten from your architect. Planning Permission is different from consent for use of premises or land. Consent allows you to use the property for the purpose it was originally intended for while planning permission allows you make alterations on the structure or use it for a different purpose.
If you proceed in carrying work on your property without first seeking and receiving planning permission (except in the situations where planning permission is not needed), you could face prosecution under the law and made to undo whatever changes you have already done.