A rear extension, loft or outbuilding went up without permission, or not quite as approved. We measure what is there, draw it as built, make the planning case and send the application to your council.
(£565 if you supply measured drawings)
Retrospective planning application
Fixed in writing after a free assessment of your property. Council planning fees are separate.
Every price is the total you pay. Checked 24 October 2026.
Building first and asking later is not a criminal offence. Planning law treats it as a breach that the council may or may not act on, and the same law gives you a route to put it right: section 73A. The officer asks one question, the same as for any extension. Is it acceptable in planning terms where it stands?
That question is easier to answer on a built structure. The case officer can see the eaves, the neighbour's window and the street from the pavement. A well-drawn as-built set shows the council exactly what it is being asked to approve, and often a small amendment on paper, such as obscure glazing or a lower parapet, is enough to tip a borderline case.
We see three situations again and again in London: a rear extension built deeper than the permission allows, a loft converted under permitted development that turned out not to qualify, and a garden building used as a bedroom. Each starts with a measured survey, because the drawings must match the structure to the centimetre.
If the work would have needed no application at all, we say so before you pay for drawings. A lawful development certificate may be the cheaper and cleaner answer.
Five steps from the survey visit to the decision notice.
Enforcement is a risk with a long tail, not an immediate one, but it affects your options the longer a breach stands.
| Situation | What the law says | What it means for you |
|---|---|---|
| No notice served yet | Council has 10 years to act on most breaches in England | You can apply now on your own timetable |
| Enforcement notice served | Appeal must be made before the date the notice takes effect | Apply and appeal, and speak to us the same day |
| Council declines to decide | Section 70C applies where a notice came before the application | Appeal route on ground (a) instead |
| Selling or remortgaging | Solicitors ask for permission or a certificate | A granted application clears the question for the buyer |
Sources: TCPA 1990 s.171B, s.70C and s.174. Not legal advice.
Councils validate a retrospective application like any other, so the pack has to be complete, measured and honest about what was built. Yours includes:
Each figure links to the law or the government page it comes from.
Section 73A of the Town and Country Planning Act 1990 lets a council grant planning permission for development carried out before the date of the application.
Source: legislation.gov.uk, Town and Country Planning Act 1990, s.73AIn England a council has 10 years to take enforcement action against operational development, a change of use to a single dwelling, or any other breach of planning control.
Source: legislation.gov.uk, Town and Country Planning Act 1990, s.171BAn appeal against an enforcement notice can rest on 7 grounds, from (a) to (g), and ground (a) is that planning permission ought to be granted.
Source: legislation.gov.uk, Town and Country Planning Act 1990, s.174A council may decline to determine an application that would grant permission for matters already covered by an enforcement notice issued before the application arrived (section 70C).
Source: legislation.gov.uk, Town and Country Planning Act 1990, s.70CIf you received an enforcement notice after a refusal, you must appeal by the sooner of 28 days from receiving the notice or 6 months from the date on the decision letter.
Source: GOV.UK, Appeal a householder planning decisionThe fees guidance lists retrospective applications, where development has already taken place, among those that carry a planning fee (paragraph 003).
Source: GOV.UK, Fees for planning applications, paragraph 003London councils decided 24,758 householder applications in the year to March 2026.
Source: GOV.UK, Planning applications statistics (PS2)Tell us about your project and get a fixed, no-obligation quote back within one working day. If you don't need planning permission at all, we'll tell you that too — for free.
No. Section 73A has no cut-off. In England the council has 10 years to enforce against most breaches, so an older structure is often immune from action, but proving that needs evidence. We can apply for permission or advise on whether a lawful development certificate for existing work suits you better.
Only if it serves an enforcement notice, and you can appeal that notice. Most councils prefer a workable application to a demolition order when the harm is small. We draw as built and, where a small change would remove an objection, show that change on the drawings.
The council fee is the standard planning fee for the work. Our own part is £765 inc survey, including the as-built survey. If you already hold measured drawings of the structure as it stands, it comes down to £565.
Yes, nothing in law stops you using the building while an application is pending. Be careful about finishing further work, though. Anything added now widens the breach and weakens a request for sympathy. Pause until the decision.
That is a contract matter between you and the builder, and we cannot advise on it. Keep the quote, messages and invoices. We can supply the as-built drawings and a note of where the work departs from the rules, which solicitors often ask for.
A refusal states its reasons, and you can appeal. We look at whether the drawings can change to meet the reasons and, if not, whether an appeal on a householder basis is worth the effort. Householder appeals have a 12-week deadline from the decision letter.
Possibly. Planning permission and building regulations are separate. If the work was built without building control, a regularisation certificate is a separate route, and we can prepare that pack as well.
Answer five quick questions and get a free planning score for your exact address — instantly. Then, if you want the full picture, unlock the detailed analysis: your council's live approval rates, local precedents, constraints on your street and a step-by-step route to permission.