Enforcement warning notices and how to respond to one

An enforcement warning notice is an invitation, not an order. It tells you the council believes there has been a breach of planning control, that permission might realistically be granted if you applied, and that you should apply within a stated period. Nothing has to be pulled down. Nobody has committed an offence by receiving one. What it does mean is that the authority has looked at your property, formed a view, and started a file, and the choice you make in the next few weeks determines how the rest of it goes.

What an enforcement warning notice is and who issues it

The power was created by section 117 of the Levelling-up and Regeneration Act 2023, which inserted a new section into the Town and Country Planning Act 1990. A local planning authority may issue the notice where it appears that there has been a breach of planning control and there is a reasonable prospect that permission would be granted if an application were made.

The notice must say what the breach is and invite an application by a stated date. It will also warn that further enforcement action may follow if nothing is submitted.

The enforcement provisions of the 2023 Act were brought into force in England during 2024, and the extended immunity period they introduced applies to breaches occurring on or after the relevant date. Check the relevant regulations for the date that applies to your situation, because the position for an older breach may be different.

There is no appeal against a warning notice. That is not a gap in the legislation. It follows from the notice requiring nothing of you.

How it differs from a planning contravention notice

The two arrive in similar envelopes and do very different things.

A planning contravention notice under section 171C of the 1990 Act requires answers, and the answers can be used later. Take advice before completing one, answer honestly, and do not guess at dates. An enforcement notice proper is different again: it requires specified steps within a specified time, and it carries a right of appeal on the statutory grounds.

The invitation to apply for retrospective permission

The application route is section 73A of the 1990 Act, which allows permission to be granted for development already carried out. The form, the fee and the validation requirements are the same as for the equivalent prospective application.

Two features to plan for. First, the application is publicised in the normal way, so neighbours who complained will be consulted again. Second, the description of development has to describe what is actually there, measured and drawn accurately, which for an unauthorised conversion often means a measured survey before anything else.

Where the breach is a use rather than building work, the description matters even more. "Change of use from dwellinghouse (Class C3) to house in multiple occupation (Class C4)" is not the same application as one describing a large HMO in a sui generis use, and getting the class wrong wastes the fee.

What happens if you ignore it

Usually an enforcement notice, in its own time. The authority has the evidence it needs, it has offered you a route, and the file records that you did not take it.

That matters at appeal. An inspector considering an enforcement notice appeal will know the warning notice was issued, and an applicant who ignored an invitation to regularise has less to say about proportionality. It can also matter on costs.

The other consequence is commercial. An unresolved enforcement file shows up on a local land charges search and in the council's enforcement register, and it will be found by a buyer's solicitor or a lender's valuer. The practical cost of putting an unauthorised development right is set out in the notes on the cost of an unauthorised development put right.

Deciding whether to apply or to argue immunity

This is the real decision, and it turns on dates.

Immunity works by the passage of time. Historically the periods were four years for operational development and for change of use to a single dwellinghouse, and ten years for other changes of use and for breaches of condition. The 2023 Act moves to a single ten-year period for breaches occurring after the relevant date, so work out which regime applies to your breach before anything else.

If the breach is already immune, the route is a certificate of lawfulness of existing use or development under section 191 of the 1990 Act, not a retrospective planning application. A certificate confirms the position permanently. A retrospective permission for something that was already immune wastes a fee and can attach conditions you did not previously have.

If the breach is not immune and permission is realistically available, apply. If it is not immune and permission is not realistically available, take advice before doing either, because a refused retrospective application hands the authority an enforcement notice on a plate.

One trap worth knowing. Section 70C of the 1990 Act allows an authority to decline to determine a retrospective application where an enforcement notice has already been issued for the same matter. Applying early, while the invitation is open, preserves an option that closes later.

Evidence to gather before replying

For an immunity case, the burden is on you, and it is judged on the balance of probabilities. Assemble a continuous record rather than a good one.

• dated photographs, including any with visible date stamps or metadata
• tenancy agreements, rent books and deposit protection records
• council tax records, including any banding changes
• utility bills and supply records showing separate connections
• electoral roll entries
• invoices from builders, with dates and descriptions
• statutory declarations from neighbours, tenants or contractors

Gaps are what lose these cases. A four-year record with an unexplained eight-month hole in the middle invites the argument that the use ceased and restarted.

For a retrospective application, the evidence is different: a measured survey, drawings of what exists, and a Planning Statement addressing the policies the officer will apply, including amenity, parking and any Article 4 direction covering conversions in that area.

Timescales and what follows

Reply within the period the notice gives, even if the reply is to say that an application is being prepared and to ask for a short extension. Silence is read as refusal to engage.

Where you apply, the usual eight weeks runs from validation. Where you seek a certificate, the same period applies and the decision is a matter of fact and law rather than planning merits. Where the council proceeds to an enforcement notice, you have at least 28 days before it takes effect and a right of appeal within that window, and lodging the appeal suspends the notice.

The broader sequence, from complaint through investigation to notice, is set out in the notes on what happens after an enforcement complaint. Reform of the enforcement regime is one of the areas still being brought into force in stages, and updates are tracked on the planning law timeline.

Enter your postcode on PlanScope to see which reports a retrospective application would need. This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.