Retrospective planning permission

General guidance, not advice. This guide explains how UK planning law works in general terms. It is not legal or planning advice for your specific site, and the law changes over time and differs between England and Wales. Check the current rules with your local planning authority or a qualified planning professional before you act.

Retrospective planning permission is an application under section 73A of the Town and Country Planning Act 1990 to regularise development that has already been carried out. It covers three situations set out in section 73A(2): works done without planning permission; works done under a temporary permission that has now expired; and works that breached a condition on an existing permission. If the council grants it, the permission can take effect from the date the development was actually carried out (section 73A(3)) - so it regularises the past breach rather than simply authorising future use.

Crucially, the council decides a retrospective application on the same planning merits as a normal application: the development plan, national policy, and any other material considerations. The fact that the works are already built does not by itself make them acceptable, and it does not by itself make them unacceptable. What changes is the context - you are applying after the event, often with the council's enforcement team already involved.

What is retrospective planning permission?

Section 73A(1) of the Town and Country Planning Act 1990 lets a local planning authority grant planning permission for "development carried out before the date of the application." That is the statutory hook for every retrospective application in England and Wales - the TCPA applies to both jurisdictions.

An application under section 73A is made, validated, publicised and determined in the same way as any other planning application. The difference is in the effect of the permission: under section 73A(3), the council may grant it so that it takes effect from the date the development was carried out (or, for a temporary permission that has expired, from the end of that period). This backdated effect is what cures the historic breach of planning control. The application fee, publicity, neighbour consultation and determination period are the same as for an equivalent forward application.

It is not an amnesty. The council can still refuse it, and a refusal leaves the breach live - at which point enforcement remains on the table.

When do you need a retrospective application?

You need one whenever there has been a breach of planning control. Section 171A(1) of the TCPA defines a breach as either:

• carrying out development without the required planning permission - for example, building an extension, erecting an outbuilding, or changing the use of land without permission; or
• failing to comply with a condition or limitation on a planning permission that has been granted - for example, breaching an occupancy condition, an operating-hours limit, or a landscaping requirement.

Common triggers include: works begun in the genuine belief they were permitted development but which fall outside the GPDO limits; a change of use that has crept up over time (a single dwellinghouse quietly becoming a small HMO, or a unit drifting from one use class to another); and works done by a previous owner that only come to light on conveyance or a local land charge search.

For condition breaches specifically, the council also has a separate tool - the breach of condition notice under section 187A. A breach of a condition is itself a breach of planning control (section 171A(1)(b)), and serving a breach of condition notice counts as enforcement action under section 171A(2), so it is normally subject to the 10-year limit for "any other breach of planning control" in section 171B(3). The exception is section 171B(4)(a): that limit does not apply where an enforcement notice in respect of the breach is already in effect. A retrospective application under section 73A(2)(c) is still the route to regularise the breach if the condition itself is no longer appropriate, but you may also need to apply to vary or discharge the condition under section 73.

The enforcement risk: time limits and notices

If you do nothing, the council can take enforcement action. Under section 172, the council may issue an enforcement notice where there has been a breach of planning control and it is expedient to do so, having regard to the development plan and any other material considerations. The notice can require you to remove buildings or works, stop an activity, or restore the land to its previous condition (section 173).

Enforcement is time-limited. Section 171B sets the deadlines within which the council must act, and they differ between England and Wales:

• England: ten years for operational development (building, engineering, mining or other operations), running from the date the operations were substantially completed; ten years for a change of use of a building to a single dwellinghouse, running from the date of the breach; and ten years for any other breach, running from the date of the breach.
• Wales: four years for operational development (from substantial completion); four years for a change of use of a building to a single dwellinghouse (from the date of the breach); and ten years for any other breach (from the date of the breach).

Once the relevant period expires, the council can no longer take enforcement action, and the development can become lawful - which is the basis for a lawful development certificate (see below). Note the England position: the four-year rule for operational development and for change of use to a single dwellinghouse was extended to ten years, but the test turns on when the breach occurred. The ten-year limit applies where the operational development was substantially completed, or the change of use took place, on or after 25 April 2024; works completed before that date keep the old four-year rule (so a conversion or extension finished a few years ago may already be immune at four years). Wales retains the four-year period.

Three options when you have unauthorised works

If you discover - or are told - that works are unauthorised, you broadly have three options. The right one depends on how long ago the breach occurred, how strong the planning case is, and whether the council is already in enforcement.

1. Apply for retrospective planning permission

Best when the breach is recent (well within the section 171B time limits) and the works are defensible on planning merits. You make a section 73A application, pay the fee, and the council determines it like any other application. If granted, the permission backdates to when the works were done. If refused, you can appeal the refusal to the Secretary of State under section 78, or revise and resubmit.

2. Apply for a lawful development certificate (LDC)

If the relevant time limit in section 171B has already expired, the development may have become lawful by immunity. Rather than asking the council to grant permission, you apply under section 191 for a certificate of lawfulness of existing use or development, which asks the council to certify that the use or works are lawful. The test is different: it is a legal question (is it immune from enforcement?) rather than a planning-merits question (should permission be granted?). See our lawful development certificates guide for the detail. Applying for retrospective permission when you should be applying for an LDC is a common and expensive mistake - it invites the council to refuse on merits when the works are already lawful.

3. Accept the breach and remediate

If the works are clearly unacceptable and not defensible, the cheapest route may be to comply: remove the unauthorised building, cease the unauthorised use, or restore the land. This avoids the cost and risk of a refused application, a contested enforcement notice, and the criminal liability that attaches to non-compliance with an enforcement notice (section 179). It is also the cleanest outcome if you plan to sell - a satisfied enforcement notice is less of a blight on title than an open breach.

Is retrospective planning permission harder to get?

It can be - but not because the council applies a stricter policy test. The legal test is the same. The difficulty is contextual, and it comes from two places.

First, the council may already be in enforcement. If an enforcement notice has been issued, the conversation is no longer a forward-looking planning debate - it is an attempt to work around a formal regulatory act, and the enforcement team rather than the case officer is driving it. The notice itself specifies a compliance period, so you may be racing the clock at the same time as your application is determined. There is a further trap here: under section 70C the council can decline to determine a retrospective application altogether once an enforcement notice has been issued. You get only one opportunity to obtain permission after the event - a section 73A application or a ground (a) appeal against the enforcement notice, not both - so applying retrospectively after enforcement does not guarantee your application is even considered.

Second, there is no pre-application stage to test and shape the proposal. A normal application usually benefits from pre-application advice, where you adjust the scheme before it is formally judged. With unauthorised works already on the ground, you are largely stuck with what exists, so the council's first formal look at the scheme is also its determination. That makes the application more adversarial and leaves less room to negotiate.

There is also a specific statutory interaction to be aware of in England. Under section 174(2A) of the TCPA, if the council issues an enforcement notice after you have made a related planning application for the same development, you cannot appeal that enforcement notice on the ground that "planning permission ought to be granted" (ground (a) under section 174(2)) where the notice was issued while the application was under consideration, or within two years of it ceasing to be under consideration. Under section 174(2AB) the restriction does not apply to a notice issued more than two years after the application ceased to be under consideration - so a ground-(a) appeal remains available in that later window. For a notice issued within the two-year period, ground (a) is permanently barred; the bar does not lift once the two years expire. The practical effect: making a retrospective application can, in England, foreclose the appeal route on a later enforcement notice issued while it is being considered or shortly after - so the timing of a retrospective application relative to any enforcement action matters.

How to give your retrospective application the best chance

A retrospective application succeeds when it looks like a well-evidenced planning case, not an apology. Six practical steps:

1. Gather evidence of the works and their dates. Dated photographs, builder invoices, delivery notes, satellite imagery timestamps, and utility connection dates all help establish when the development was carried out. This matters for two reasons: it tells you whether the section 171B time limit has expired (and therefore whether you should be applying for an LDC instead), and it pins down the "substantial completion" date for any operational development.
2. Identify the reason the council would object - and answer it. If the breach is amenity-related (overlooking, loss of light, noise), address the amenity impact directly with a planning statement or mitigation. If it is policy-based (green belt, conservation area, listed building), show how the works comply or how the harm is limited. A retrospective application that ignores the obvious objection will fail for the same reason a forward application would.
3. Check the time limit before you choose the route. If you are past the section 171B deadline in England or Wales, a lawful development certificate under section 191 is likely the better application - it asks the right legal question and does not invite a merits-based refusal.
4. Consider pre-application advice even now. Some councils will engage on a retrospective basis before you formally submit, particularly if you are open to amendments. It is cheaper than a refused application and tells you the case officer's view before you commit to the fee.
5. Get the description right. The application description must accurately reflect what was actually built. Describing the works as something narrower than what exists - or broader - creates validation problems and can undermine the permission if it is later challenged.
6. Do not wait for the enforcement notice. Applying before formal enforcement puts you in the position of someone seeking to regularise, not someone responding to an allegation. Councils generally look more favourably on voluntary regularisation than on applications made under the pressure of a live notice.

If an enforcement notice has already been served, you still have rights: you can appeal to the Secretary of State under section 174, including on the ground that the time limit had expired when the notice was issued (ground (d)), or on the ground that the steps required exceed what is necessary to remedy the breach (ground (f)). The appeal must be made before the notice takes effect. See our appeals guidance for how appeal odds vary by council and by issue.

The cleanest position is always to have had permission before you built. The next best is to understand which of the three routes - retrospective permission, an LDC, or remediation - actually fits your situation, and to run that route with the evidence and the planning argument the council will use to decide it. GapSense exists to help you see that argument before you submit: see how it works, or read our council guides for the local policy landscape where your site sits.

Disclaimer: this guide is general information, not legal or planning advice, and reading it does not create any professional relationship. Planning law and national policy change, and vary between England and Wales. Always confirm the current position with the relevant legislation, your local planning authority, or a qualified planning consultant before making a decision.

Sources: the Town and Country Planning Act 1990 (sections 73A, 171A, 171B, 172 to 174, 187A and 191), the National Planning Policy Framework (December 2024), and Planning Policy Wales (Edition 12). Time limits reflect the consolidated legislation as at July 2026; always check the live legislation and your council's local position.