Enforcement time limits for change of use after the 2023 Act
Which immunity period applies depends on when the breach began. The transitional position matters more than the headline rule, and continuity is what has to be proved.
Enforcement immunity for a change of use in England is now a single ten year period, following amendments made by the Levelling-up and Regeneration Act 2023 that took effect in 2024. The older split, four years for operational development and for change of use to a single dwellinghouse and ten years for everything else, still governs breaches that occurred earlier. So the first question in any case is not which rule applies today. It is when the breach began.
Get that date wrong and the whole analysis collapses.
The four and ten year rules and what they covered
Section 171B of the Town and Country Planning Act 1990 has always set out the periods after which no enforcement action may be taken.
Historically it worked like this. Four years from substantial completion for operational development, meaning building, engineering, mining or other operations. Four years from the date of the breach for a change of use of a building to use as a single dwellinghouse. Ten years for any other breach of planning control, which covered other material changes of use and breaches of condition.
The four year rule for single dwellings was the one that generated most of the reported litigation, because it created a strong incentive to keep an unauthorised conversion quiet for four years. That is a large part of why it was changed.
Immunity is not a permission. It removes the ability to enforce, and it makes the use lawful for the purposes of the Act, but it does not grant planning permission and it does not authorise anything beyond what has actually been happening.
What the Levelling-up and Regeneration Act 2023 changed
The 2023 Act amended section 171B so that, in England, a single ten year period applies to all breaches of planning control. The change came into force in 2024.
Two features of the reform matter in practice.
The first is that it is forward looking. Immunity that had already accrued before the change is preserved, so a use that had run its four years and become lawful stayed lawful.
The second is that the change is England only. Wales retains its own arrangements, so a practitioner working across the border needs to check which regime applies.
Because the transitional provisions do the real work here, read the current text of section 171B together with the order that brought it into force rather than relying on any summary, including this one. The precise dates matter when a breach began close to the changeover.
How the transition affects existing breaches
Work through it in this order.
- Identify the breach precisely: what use, in what building or on what land, and how it differs from the lawful position.
- Date the start of the breach with evidence, not recollection.
- Establish whether the breach was continuing at the date the reform took effect.
- Apply the period that governs a breach beginning on that date.
- Check whether the period had already expired before the reform, in which case immunity is preserved.
The awkward cases are the ones where a four year period was running but had not expired when the change took effect. Those need careful reading of the transitional provisions and, frequently, advice.
An illustrative example: a single flat created in the roof space of a commercial building. If it was first occupied as a dwelling in 2018 and occupied continuously since, the four year period expired in 2022 and the use became lawful before the reform. If it was first occupied in 2023, the analysis is materially different and depends on the transitional wording.
Concealment and the effect on immunity
Deliberate concealment sits outside the ordinary time limits. Where a breach has been deliberately concealed, a council may apply to a magistrates court for a planning enforcement order, and if one is granted the authority regains the ability to take enforcement action even though the normal period has passed.
The provisions exist because of cases where owners built or converted, concealed the fact, and then claimed immunity once the period expired. Courts and inspectors take a firm view of deliberate deception.
That has a practical consequence for advisers. An application for a certificate of lawfulness draws the council's attention to the breach, and where there is a concealment element the application can prompt exactly the action the owner hoped to avoid. Assess that risk before applying, not afterwards.
Evidence needed to establish continuous use
Continuity is where most immunity arguments actually fail. The period must run without a substantial break, and the applicant carries the burden of proof on the balance of probabilities.
Assemble evidence that covers every year, from more than one direction.
- Tenancy agreements, rent records and deposit protection entries.
- Council tax and business rates records, including the banding history.
- Utility accounts, meter readings and supply contracts.
- Trading records, accounts, licensing returns and staff payroll summaries.
- Dated photographs and historic aerial imagery.
- Statutory declarations from people with first-hand knowledge across the period.
Where the use has physical consequences, the installation records help date it. For a food business, extraction equipment invoices and maintenance records fix the start of the use, and a Ventilation and Extraction Statement describing the installed system provides a technical description of what has actually been operating.
Gaps are not automatically fatal, but they must be explained. A three-month void between tenants is ordinary. A property boarded up for eighteen months invites an argument about abandonment.
Breach of condition notices and their separate position
Conditions occupy their own territory. A breach of condition can be pursued by an enforcement notice or by a breach of condition notice, and the latter has no right of appeal to the Planning Inspectorate, which makes it a blunt and effective tool.
Immunity still accrues for a continuing breach of condition over the relevant period. But intermittent breaches do not accumulate. A condition limiting opening hours that is breached in some months and observed in others will rarely produce immunity, because the breach is not continuous.
Where a condition has become impractical, the better route is an application under section 73 to vary it, supported by evidence of why the original condition no longer serves its purpose. On hours and activity conditions that usually means the same evidence a council would want anyway: a Transport Statement on servicing and trips, or a parking survey where street parking is the underlying concern.
Recording use so immunity can be proved
The advice for anyone operating on the margins of what is authorised is simple and rarely followed. Keep a dated record, contemporaneously, of what the property is used for.
A single file with an annual entry, supported by two independent documents per year, is enough. Add photographs. Keep the file with the deeds rather than on a phone.
When the time comes to apply for a certificate, that file turns a difficult evidential case into a straightforward one. Set the argument out in a Planning Statement that identifies the breach, the start date, the applicable period, the evidence for continuity and the legal conclusion, in that order.
This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. A lawful development certificate is the only formal way to confirm that a use or works are lawful. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Which time limit applies to my breach?
It depends on when the breach occurred. Breaches that began before the 2023 Act change took effect are governed by the old periods, four years or ten years depending on the type of breach. Breaches beginning after that date attract the single ten year period in England. Establish the start date before deciding which rule to argue.
Does the ten year period apply retrospectively?
No. A breach that had already run its four year period and become lawful before the change does not lose that status. The reform is forward looking, and the transitional provisions preserve accrued immunity. That is why cases turning on a change of use to a single dwelling in the early 2020s still need careful dating.
What counts as continuous use?
Use that has carried on without a substantial interruption throughout the relevant period. Short vacancies between tenants are usually tolerated. A property standing empty for a year, or reverting to a different use for a period, may break continuity or amount to abandonment, and either outcome restarts the clock.
Are breaches of condition treated the same way?
Broadly, yes, though the mechanics differ. A breach of condition can be dealt with by an enforcement notice or by a breach of condition notice, and immunity for a continuing breach accrues over the same period. A condition breached, remedied and breached again does not accumulate time across the gaps.
How do I establish the position formally?
Apply for a certificate of lawfulness for the existing use. That converts an argument about immunity into a determination you can rely on, and it is what buyers, lenders and insurers ask for. The burden of proof sits with the applicant, on the balance of probabilities, and the case is decided on evidence rather than planning merits.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.