Enforcement Time Limits: the 10 Year Rule, and when 4 Years still applies

One of the oldest ideas in planning is that a breach of control does not stay enforceable forever. Leave it long enough, and the council loses the power to act – the development becomes immune, and can then be confirmed as lawful. These are the planning enforcement time limits, and they are the most misunderstood corner of the whole system.

They are misunderstood partly because the law changed. For decades people spoke of a “four-year rule” and a “ten-year rule”. In England, that split was swept away on 25 April 2024: there is now a single ten-year limit for almost everything, with the old four-year period surviving only in narrow, transitional circumstances. Get the date wrong and you can badly misjudge whether a breach is safe or still exposed.

This page explains the current position in England, when the four-year rule can still apply, what “immunity” really means, and why time alone is never quite the whole story. It forms part of our planning enforcement guidance. Anyone on the other side of this, wondering whether it is worth reporting something before the clock runs out, should read our guide on how to report a breach of planning control. If you are counting the years because somebody has just reported you, our page on being reported to planning enforcement explains what the council does next.

The position in England today

Since 25 April 2024, a single time limit applies to breaches of planning control in England: no enforcement action may be taken once ten years have passed. The change was made by section 115 of the Levelling-up and Regeneration Act 2023, which amended section 171B of the Town and Country Planning Act 1990, and it was brought into force by commencement regulations (SI 2024/452).

The clock runs differently depending on the kind of breach, even though the length is now the same:

• building, engineering, mining or other operations – ten years from the date the operations were substantially completed
• a change of use, or a breach of condition – ten years from the date the breach occurred, or the date the condition was first breached

The practical effect is that anyone relying on the passage of time in England now needs to show a full ten years, for example, ten years of continuous residential use, or ten years since a building was finished. That is a longer and more demanding evidential burden than the old four-year rule ever imposed.

When the four-year rule still applies

The four-year rule has not vanished entirely. The 2024 change is not retrospective, and a transitional provision preserves the old four-year period in two specific situations – broadly, where the relevant event happened before 25 April 2024:

• operational development (building, engineering and the like) that was substantially completed before 25 April 2024
• a change of use of a building to use as a single dwellinghouse where the breach occurred before 25 April 2024

In those cases the breach could already have become immune under the four-year rule, and that immunity is not undone by the new law. This is why the completion date, or the date a dwelling use began, matters so much: a barn conversion finished in early 2024 may sit under the four-year rule, while the identical conversion finished a month later falls under ten years. If your position depends on that boundary, the evidence of when becomes the whole case, and it is worth taking advice before you rely on it.

What “immune” actually means

Immunity is a genuinely useful idea, but it is narrower than people hope. Once a breach has run past its time limit, the council can no longer take enforcement action against it – and a use or operation that is immune can be confirmed as lawful through a certificate of lawfulness of existing use or development. That certificate is the formal proof that the development is now beyond enforcement.

But immunity attaches to the specific breach, proven over the specific period. Two things routinely undo it. First, the use must have been continuous and genuine throughout – gaps in occupation, or a use that stopped and restarted, can break the count and leave you short. Second, the time only helps you if you can prove it: the burden is on you, on the balance of probabilities, and unsupported assertion rarely carries the day. Photographs, bills, tenancy agreements, electoral roll entries and the like are what make or break these cases.

An immune use can also slip away in a manner that surprises people. If the land later changes to something else, the immune use is not left sitting there for you to pick up again whenever you choose. Changing back to it is itself a material change of use, and it needs planning permission. The exception is where the council serves an enforcement notice against the later use, because a separate right can then let you return to what went before. Our page on reverting to a previous lawful use explains how that works, and where its limits sit.

Concealment stops the clock

There is an important exception for those tempted to run the clock down quietly. Where a breach has been deliberately concealed, the council can apply to a magistrates’ court for a planning enforcement order, which allows action to be taken even after the normal time limit has passed. The provisions sit at sections 171BA to 171BC of the 1990 Act, and they exist precisely to stop someone hiding an unlawful development until it appears immune and then claiming the benefit of the very concealment.

The lesson is straightforward: time only protects an open, honest breach. Concealment does not buy immunity – it can forfeit it, and it invites a far harsher view all round.

What actually stops the clock, and what does not

This is where people go wrong. The assumption is that any letter from the council freezes the countdown. It does not. The Act sets out a short, closed list of what counts as the council taking enforcement action, and in England it is only these three:

• an enforcement notice
• a breach of condition notice, which carries no right of appeal at all
• an enforcement warning notice, which is the step where the council tells you to apply for permission instead, and which has only counted since 25 April 2024; issuing one also opens a further four year window for the council to come back

Nothing else on that list. So a planning contravention notice, a section 330 notice and even a temporary stop notice all leave the clock running, and so does the whole of a planning enforcement investigation, site visits and warrants included. The council can send you any of them, read your answer, and the countdown carries on the whole time.

There is a second-bite rule that catches people out. If the council has already taken, or tried to take, enforcement action over the same breach, it gets a further window in which to take more, even though the main period has expired. That window is four years, and it was left untouched when the main limits in England moved to ten years, so the two numbers now sit side by side meaning quite different things.

Time is not the only question

It is tempting to treat the calendar as the whole answer, but two other things sit alongside it. The first is that listed buildings and protected trees run to different rules – there is no equivalent immunity period for unauthorised works to a listed building, so the passage of time does not make that kind of breach lawful. The second is that the date of the breach, not the date you are counting from today, is what matters, and pinning that date down is often the hard part.

It is also worth remembering that becoming immune is not the same as having permission. An immune use is lawful, but it carries no planning permission and no conditions – which can matter later if you want to change or extend what you are doing. Where the position is finely balanced, our page on the 10 year rule and certificates of lawfulness explains how to turn immunity into a certificate you can rely on.

Is there a cost, and can you challenge the council’s view?

Working out a time-limit position costs nothing in itself, but proving it usually means an application for a certificate of lawfulness, and that carries a fee: a certificate for an existing use is charged at the same rate as a full planning application for the same development, and a certificate for a proposed use at half that. Other applications, such as retrospective planning permission if immunity cannot be shown, also carry fees. Fees are set nationally and change from time to time, so our planning application fees guide explains the position.

If the council disagrees with you – refusing a certificate, or serving an enforcement notice on the view that the time limit has not run – you are not without recourse. A refused certificate can be appealed to the Planning Inspectorate, and an enforcement notice can be appealed under section 174, one of whose grounds is precisely that the time for enforcement has expired, which is ground (d). Our page on the enforcement appeal grounds sets out what you have to prove to win on it, and where the burden falls. Our guide to planning appeals sets out the routes and deadlines, and our enforcement notices page deals with the notice itself. The one thing not to do is let a deadline slide: enforcement appeal periods are short and unforgiving.

See also our guide to the planning enforcement process.

Enforcement time limits relevant legislation

The primary sources below are on legislation.gov.uk. Check the “Changes to Legislation” panel at the top of each page for any amendments not yet incorporated into the revised text.

• Town and Country Planning Act 1990, s171B – time limits (ten years in England from 25 April 2024)
• Levelling-up and Regeneration Act 2023, s115 – the amendment that introduced the single ten-year limit
• Town and Country Planning Act 1990, ss171BA–171BC – planning enforcement orders where a breach has been concealed
• Town and Country Planning Act 1990, s191 – certificate of lawfulness of an existing use or development

Other Enforcement Sections

Enforcement Time Limits Page Updated: 15th August 2026