Under-enforcement: when complying gives you planning permission

 

Under-enforcement is one of the very few parts of planning enforcement that works in your favour. It happens when a council serves an enforcement notice that could have told you to pull something down or to stop doing something, but does not go that far. Do everything that notice asks, and the law treats you as having planning permission for whatever it let you keep.

You do not apply for this. There is no form, no fee and nothing to fill in. It happens on its own, the moment you have complied in full.

The catch is in those last two words. Comply with most of the notice and you get nothing at all.

This page covers England and Wales. The rule sits in section 173(11) of the Town and Country Planning Act 1990, which has not been altered since it came into force in 1992 and works the same way in both countries. It sits inside our wider guide to planning enforcement.

Whilst we are happy to give you some help via this page, it is often easier to consult a professional. If in doubt – STOP – and reach out to us. We are here to help. Contact us here. 

 

What under-enforcement actually means

 

The name is a poor one, and it puts people off a rule that could save them a building. It simply describes a council that has taken enforcement action but has asked for less than the full remedy it was entitled to ask for.

Say you built a garage without permission and it is a metre too tall. The council could have required the whole garage to be taken down. Instead the notice only requires the roof to be lowered. You lower the roof. At that moment the garage, which they could have made you demolish, is treated as having planning permission.

The council does not have to intend this, and it does not have to agree to it. It is simply what the Act says happens.

 

The two things that have to happen

 

Both of these have to be true, and there is no partial credit:

• the notice could have required the buildings or works to be removed, or the activity to stop, and it did not do so
• every single requirement of the notice has been complied with

If both are met, permission is treated as granted, but only so far as the notice did not require removal. In plain terms, you get permission for the part they let you keep, and nothing more.

The second condition is full compliance. A notice often carries several requirements, sometimes with different compliance periods. Doing four out of five means the rule does not bite. Missing a compliance deadline is a different issue: it can expose you to criminal liability once the compliance period has expired, but section 173(11) itself asks whether all the requirements of the notice have been complied with, not whether every step was completed on time. Late compliance does not erase any earlier offence, so work through the notice line by line and take both the requirements and the deadlines seriously.

 

What “could have required” means

 

This is the part that decides most cases, and it is decided by the notice itself rather than by what the council might have done in theory.

Near the top of every enforcement notice is a paragraph setting out the matters that appear to the council to be the breach of planning control. That paragraph does the work. If it says the whole building is unauthorised, then the notice could have required the whole building to go, and under-enforcement can hand you permission for whatever survives. If it says only that the roof is too high, then removal of the whole building was never on the table, so complying gains you nothing extra.

Read that paragraph before you read the requirements. It sets the ceiling on what you can be given.

 

What you get, and what you do not get

 

The permission you end up with is treated as having been granted under section 73A, which is the same route used for a retrospective planning application. It covers what is left, as it stands.

What it does not do is just as important:

• it does not remove the notice from the council’s enforcement register, where it stays and will show up on searches when you sell
• it does not undo the breach, or wipe out a prosecution for failing to comply before you put things right
• it does not give you permission for anything the notice did require you to remove or stop
• it does not arrive with any paperwork, so nobody sends you a permission to file

 

The replacement building version

 

There is a second, much less well known limb of the same rule, and it deals with demolition.

Where the breach was pulling a building down, a notice can require you to put up a replacement that is as close to the original as possible. If the notice does that, and you build the replacement exactly as required, planning permission is treated as granted for that new building. Again it happens automatically, by the same section 73A route.

It is rare, but it matters if it happens to you, because otherwise you would have built a whole new building with no permission for it.

 

What under-enforcement does not cover

 

This rule applies to enforcement notices and nothing else. Complying in full with any of the following gives you no deemed permission at all:

• a breach of condition notice
• a stop notice or a temporary stop notice
• a section 215 notice about untidy land
• an enforcement warning notice
• a planning contravention notice

If you have one of those, doing what it says protects you from prosecution. It does not make anything lawful.

 

How this links to an appeal

 

Under-enforcement is the reward at the end of a successful argument about scope.

One of the grounds of appeal against an enforcement notice is that its requirements go further than they need to. Win that argument, get the requirements cut back, comply with what is left, and this rule then hands you permission for the rest. The two work together, and appealing on scope is often far more realistic than arguing the development should never have been enforced against at all.

That argument is ground (f), and our page on the enforcement appeal grounds works through what you have to prove to win it. The deadline and how the appeal itself runs are covered on our page about enforcement notices and how to appeal.

 

Proving it later

 

Because nothing is issued, under-enforcement leaves no paper trail, and that becomes a problem years later when you sell. A buyer’s solicitor will find the enforcement notice on the register and will want to know how it was resolved.

The way to fix that is to apply for a certificate of lawfulness, which is a formal ruling that what is there is lawful. Our guide to a certificate of lawfulness of existing use or development explains how it works. Keep your own evidence too: dated photographs, invoices and any letter from the council confirming the notice has been complied with.

 

Is there a cost?

 

Under-enforcement itself is free. There is no application and therefore no fee, because there is nothing to apply for.

Cost arrives on the routes around it. Applying for permission after the event carries a fee, and so does asking for the merits of your development to be considered as part of an enforcement appeal. If that fee is not paid in time, the ground (a) part of the appeal lapses, and so does the application, but the rest of the appeal carries on. A certificate of lawfulness carries a fee as well. Our planning fees page sets out where the charges sit and how they are worked out.

Complying with the notice will have its own cost, of course, and that is usually the real number.

 

What if the council does not accept it?

 

There is no appeal against under-enforcement, for the simple reason that it is not a decision. Nobody grants it, so there is nothing to appeal against.

If the council disputes that you have complied in full, or refuses to accept that you now have permission, you have two routes. The usual one is to apply for a certificate of lawfulness, and if that is refused there is a right of appeal. The other is judicial review, which challenges the way the council behaved rather than the planning merits, and which has short deadlines. Our page on planning appeals covers the first of those.

 

Should you be relying on this at all?

 

Honestly, no, not as a plan.

Under-enforcement is a consequence, not a strategy. You cannot ask a council to under-enforce, you cannot negotiate for it, and you have no way of knowing how a notice will be drafted until it lands. Building something in the hope that any future notice will be narrowly worded is a poor gamble, and a badly worded notice is just as likely to require the lot.

Where it genuinely helps is after the event, when a notice has already been served and you are deciding what to do. At that point it is well worth reading the notice closely, because the difference between complying fully and complying nearly is the difference between owning something lawful and owning something that can still be taken away.

Under-enforcement relevant legislation

The rule itself is section 173(11), with the replacement building version at section 173(12). Section 173 has not been amended since it came into force in 1992. Check the “Changes to Legislation” panel at the top of each page below before relying on the wording.

Section 173(11) of the Town and Country Planning Act 1990 reads:

Where—

(a) an enforcement notice in respect of any breach of planning control could have required any buildings or works to be removed or any activity to cease, but does not do so; and

(b) all the requirements of the notice have been complied with,

then, so far as the notice did not so require, planning permission shall be treated as having been granted by virtue of section 73A in respect of development consisting of the construction of the buildings or works or, as the case may be, the carrying out of the activities.

• Town and Country Planning Act 1990, s173: contents and effect of an enforcement notice, with under-enforcement at subsection (11)
• Town and Country Planning Act 1990, s73A: the route by which the deemed permission is treated as granted
• Town and Country Planning Act 1990, s174: appeals against an enforcement notice, including the ground that the requirements go too far
• Town and Country Planning Act 1990, s191: certificates of lawfulness of existing use or development
• Town and Country Planning Act 1990, s188: the register of enforcement and stop notices

Other Enforcement Sections

 

 

 

Under-enforcement Page Updated: 22nd August 2026