What happens if work was done without planning permission?

Most people discover this problem in one of two ways: a neighbour complains, or a buyer's solicitor asks a question nobody can answer. The response is the same either way — establish exactly what was built and when, work out which route is available, and take advice before writing to the council, because the first approach shapes everything that follows.

Safety

Step by step

1. Establish precisely what was built and when.Dates, drawings, photographs, invoices, delivery notes, dated aerial imagery, council tax and utility records. Evidence of date is what every route depends on, and reconstructing it years later is the hard part.
2. Check whether it needed permission at all.A surprising amount of work assumed to be unauthorised was permitted development. Work through the permitted development conditions as they stood at the time the work was done, not as they stand now.
3. Understand what enforcement actually is.The council can serve an enforcement notice requiring the breach to be remedied, which can mean altering or removing the work. Ignoring an enforcement notice is a criminal offence, even though the original breach usually was not.
4. Understand that immunity periods exist and have changed.After a period, a breach can become immune from enforcement. The periods differ by nation and by type of breach and were changed in England recently, so do not rely on a figure you have read — get current advice for your nation.
5. Consider a retrospective planning application.You can apply for permission for work already done. It is judged on the same planning merits as if it had not been built, which means it can be refused, and it puts the work formally on the council's radar.
6. Consider a certificate of lawfulness for existing development.Where the work was lawful when done, or has become immune, the council can certify that. This is the strongest outcome, because it produces a document rather than a permission granted after the event.
7. Deal with the building regulations question separately.Planning and building control are different systems and being resolved in one does nothing for the other. Unauthorised building work usually has a missing completion certificate as well.
8. Take advice before contacting the council.A planning consultant or solicitor will tell you which route is realistic and how to approach it. This is the single point in this guide where paying for an hour of advice most reliably saves money.

Tips

• If you are buying a property with unauthorised work, this is a matter for your solicitor and your survey, not something to resolve informally with the seller. Indemnity insurance is sometimes offered and it covers enforcement risk rather than the work being right.
• Contacting the council can prevent an indemnity policy from being available later. That is one of the main reasons to take advice on sequence first.
• Neighbour complaints are the usual trigger for enforcement. A good relationship with the people either side is worth more than most legal advice.

Common mistakes

• Assuming a period of time has automatically made it lawful — Immunity depends on the type of breach and on evidence of the date, the periods differ by nation, and they have changed. Assumption is not evidence.
• Applying retrospectively without checking permitted development first — If the work never needed permission, an application invites the council to assess a scheme it had no jurisdiction over, and a certificate of lawfulness was the better route.

Questions people ask