Enforcement and permitted development: who proves what
The council does not have to prove your extension needed permission. On the no-breach ground of appeal, you have to prove it did not, limb by limb.
When a council serves an enforcement notice, it does not have to prove that your works needed planning permission. You have to prove that they did not. That reversal is the whole of the permitted development enforcement burden of proof problem, and it catches owners who did the right thing and kept no records. Under section 174 of the Town and Country Planning Act 1990 you can appeal on the ground that the matters alleged in the notice do not constitute a breach of planning control, and on that ground the evidential burden sits with the appellant.
So the records you keep while building are worth more than the argument you can make afterwards.
Who proves what, and when
Three stages are worth separating.
Before any notice, the authority investigates. It may serve a planning contravention notice requiring information about the land, the works and who carried them out. Answering inaccurately or failing to answer is an offence, so answer carefully and on time, with measurements rather than impressions.
At the point of service, the authority has to be satisfied that it appears to it that a breach has occurred, and the notice has to specify the matters alleged with enough precision for you to know what you are accused of. A notice that fails to do that can be challenged, although the Planning Inspectorate can correct defects where no injustice results.
On appeal, the grounds split the burden. Ground (c), that the matters alleged do not constitute a breach, is for you to establish. Ground (d), that enforcement is out of time, is also for you. Ground (a), that permission ought to be granted, is a planning merits argument decided on the usual balance.
What you have to establish on the no-breach ground
To show the works were permitted development you have to take the inspector through the class relied on, limb by limb, and evidence compliance with each limit and condition.
For a rear extension under Part 1 Class A, that means depth from the original rear wall, height, eaves height, whether the house is on designated land, the proportion of curtilage covered, the materials, and whether the house itself is a dwellinghouse rather than a flat. For an outbuilding under Class E it means the fifty per cent curtilage test, height by roof type, position relative to the principal elevation, and whether the use is incidental to the enjoyment of the dwellinghouse.
Every one of those is a factual question, and the facts have to come from somewhere. "The builder said it was within permitted development" is not evidence of anything.
The evidence that works
| Fact in issue | Evidence that settles it |
|---|---|
| Dimensions of the works | Measured survey by a surveyor, with dimensioned drawings |
| Position of the original rear wall | Historic drawings, deeds plans, dated aerial photography |
| Extent of the original dwellinghouse | Plans from the original permission, or the 1948 position |
| Curtilage coverage | Site plan with areas calculated and stated |
| Height relative to ground level | Levels survey tied to a datum, with the datum identified |
| Materials used | Delivery notes, product references, retained samples |
| Date of substantial completion | Invoices, building control records, dated photographs |
| Designated land status | Mapping extract with the date it was obtained |
Two practical rules. Take measurements before anything is altered, because a wall rebuilt after the notice destroys your evidence. And identify the original dwellinghouse early, since the limits in Part 1 are measured against the dwelling as built or as it stood on 1 July 1948, not as you bought it. An extension added by a previous owner in 1995 counts against your allowance.
Photographs, measurements and dated records
Photographs are the least expensive evidence available and the most often missing. Take them before, during and after, from fixed positions, and keep the metadata.
- A full set of the existing building from every elevation before works start, with a ranging rod or tape in frame.
- Excavation and foundation photographs showing the position relative to the original wall.
- Progress photographs at least weekly, which also date the works for immunity purposes.
- Delivery notes and invoices filed by date, not by trade.
- A copy of the class you relied on, printed on the day you relied on it, since the order is amended periodically.
Keep a one-page note recording the class, each limit, and the figure you measured against it. Written at the time, that note is strong evidence. Written three years later, it is argument.
Why a certificate taken earlier is decisive
A Lawful Development Certificate under section 192 of the 1990 Act, obtained before building, converts the whole question into a decided fact. The council has determined that the proposed works would be lawful, and an enforcement notice cannot then be served in respect of works carried out in accordance with it.
That is worth the fee and the eight-week wait on any scheme where a limit is close, where the house has been extended before, or where the designation status is unclear. On a marginal scheme it is the single most useful document you can hold.
After the event, a certificate under section 191 does the same job for works already built, but you are now proving the facts rather than agreeing them in advance, and the evidential burden is yours.
Time limits and immunity
Immunity depends on the period that applies to your breach and on the date the works were substantially completed or the use began. Enforcement time limits in England were changed by the Levelling-up and Regeneration Act 2023, and the applicable period depends on when the breach occurred and the date the change took effect. Check the current position rather than relying on remembered figures.
Two traps recur. Deliberate concealment can extend the authority's ability to act through a planning enforcement order, so a building hidden behind hoarding does not simply run its clock. And works carried out in stages may have more than one completion date, so part of a scheme can be immune while part is not.
What to do when a notice arrives
- Diarise the appeal deadline immediately, because it is short and the notice takes effect if you miss it.
- Read the allegation and the requirements, and list the facts each one depends on.
- Commission a measured survey before altering anything.
- Assemble the records: drawings, photographs, invoices, building control, mapping.
- Decide which grounds you are running, and that they are consistent with each other.
- Prepare the class-by-class compliance note with a figure against every limit.
- Consider whether a parallel application or a certificate application helps or harms, bearing in mind that section 70C allows the authority to decline to determine an application for development already the subject of a notice.
A short Planning Statement setting out the class, each limit, your measured figure and the evidence reference for each is what an inspector wants to read. Appeals on the no-breach ground are won on tables, not on narrative.
And if you are about to build something close to a limit, spend the certificate fee now. The cost of proving compliance afterwards is many times the cost of agreeing it in advance.
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 works are lawful. PlanScope produces AI-assisted draft reports for planning applications, and reports should be reviewed before submission. PlanScope does not guarantee planning approval.
Frequently asked questions
Who has to prove that works were permitted development?
The appellant. On the ground of appeal that the matters alleged do not constitute a breach of planning control, you have to establish compliance with the class relied on, limb by limb. The authority only needs to be satisfied that it appears to it that a breach has occurred before serving the notice.
What should I do first when an enforcement notice arrives?
Diarise the appeal deadline, because it is short and the notice takes effect if you miss it. Then read the allegation, list the facts each requirement depends on, and commission a measured survey before altering anything. Altering the works destroys the evidence you need to prove compliance.
Does a lawful development certificate prevent enforcement?
A certificate under section 192 obtained before building determines that the proposed works would be lawful, so works carried out in accordance with it are protected. That is why the fee is worth paying on any scheme where a limit is close, where the house has been extended before, or where the designation status is unclear.
How are Part 1 limits measured if a previous owner extended the house?
Against the original dwellinghouse, meaning the building as first built or as it stood on 1 July 1948, not as you bought it. An extension added in 1995 counts against the allowance available to you. Establish the original footprint from the original permission, deeds plans or dated aerial photography before designing.
Can concealed works still become immune?
Not reliably. Deliberate concealment can allow the authority to apply for a planning enforcement order, which extends its ability to take action beyond the normal period. Works carried out in stages may also have more than one completion date, so part of a scheme can be immune while another part is not.
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.