Section 70C: declining to determine a retrospective application
Once an enforcement notice has been issued, section 70C of the Town and Country Planning Act 1990 lets a council refuse to consider a retrospective application for the same breach. The order in which you act decides which routes survive.
A council that has already served an enforcement notice can refuse to look at your retrospective planning application for the same breach. The power sits in section 70C of the Town and Country Planning Act 1990, and anyone facing a notice on an unauthorised HMO conversion, a flat subdivision or a barn that became a dwelling without consent needs to understand it before posting anything to the portal. A section 70C retrospective application decision is not a refusal and carries no appeal, so the sequence in which you act decides which routes stay open to you.
The provision exists to stop a second bite of the cherry. Without it, an owner could apply retrospectively, lose, then appeal the notice on the ground that permission ought to be granted, and run identical planning merits twice at public expense.
What section 70C actually does
Section 123 of the Localism Act 2011 inserted section 70C into the 1990 Act. It lets a local planning authority decline to determine an application for planning permission if the application, in whole or in part, relates to land to which a pre-existing enforcement notice relates, and granting permission would involve granting permission for the whole or any part of the matters specified in that notice as constituting a breach of planning control.
Three features of the drafting do the work.
It is a power, not a duty. An authority may decline and often does not, particularly where the application offers the tidy outcome the enforcement team wanted all along.
It can be used in part. Where an application covers both the matters alleged in the notice and other works outside it, the authority can decline the overlapping part and determine the rest. That can leave you holding a permission for the acceptable element while a live notice sits over everything else.
And there is no appeal. Declining to determine is not a decision to refuse, so section 78 does not apply and the Planning Inspectorate has nothing to receive.
Pre-existing means exactly that
The word "pre-existing" is not decorative. The enforcement notice must already have been issued when the application is made. Get a valid retrospective application in first and section 70C has nothing to bite on.
Before reaching for either route, check whether the breach is immune from enforcement at all. The historic position in England was four years for operational development and for a change of use to a single dwellinghouse, and ten years for other changes of use and breaches of condition. The Levelling-up and Regeneration Act 2023 moved those limits to a single ten-year period in England, though which regime applies turns on when the breach occurred, so confirm your dates against the current statutory position. If the works are already immune, a certificate of lawfulness under section 191 is the formal way to prove it, not a retrospective application. Councils enforce selectively and publish how they rank enforcement complaints, which is worth reading alongside the notice you have been sent.
Ground (a) and the one-bite rule
Section 174(2) sets out the grounds of appeal against an enforcement notice, and ground (a) is that planning permission ought to be granted for what the notice alleges. Section 174(2A), added by the same part of the Localism Act, removes ground (a) in England where the notice was issued after a related planning application was made but before the end of the period for determining it.
The two provisions are a matched pair.
| What happened first | Retrospective application | Ground (a) appeal |
|---|---|---|
| Notice issued before any application | Authority may decline under section 70C | Available, since no related application was pending when the notice issued |
| Application made, notice issued while it was still undetermined | Application runs to determination | Removed by section 174(2A) |
| Application refused and the statutory period expired, then notice issued | Nothing left for the authority to decline | Available, though the merits have been tested once already |
That middle row turns on precise dates, and the arithmetic is not always obvious. Compare the issue date on the notice against the date your application was validated and the eight or thirteen week period that followed. Where the dates sit close together, take advice before assuming ground (a) survives.
Choosing your route
A ground (a) appeal puts the planning merits in front of an inspector rather than a case officer who has just authorised enforcement action against you. That is a real advantage. Against it, you lose the chance to negotiate amendments, you cannot easily revise the scheme mid-appeal, and a deemed application fee is payable where ground (a) is pleaded, so check the current fee regulations before budgeting.
A fresh application gives you room to change the thing being judged. This is the most useful practical point in the whole area of law. Section 70C bites on the matters specified in the notice. Design something materially different and the overlap test may simply fail.
Illustrative example: a notice alleges use of a terraced house as a seven-bedroom HMO without permission in an Article 4 area. An application to retain seven bedrooms is squarely within the notice. An application for a five-bedroom arrangement with a rear bin store, two cycle spaces and a parking stress survey is arguably a different proposal, and the authority has to decide whether granting it would grant permission for the matters alleged. The figures here are illustrative only, but the principle holds: reduce the scheme and you may move outside the notice.
Where the merits are arguable, the supporting evidence carries the application. A proper Planning Statement that engages with the adopted plan, amenity standards and any Article 4 direction does more than a covering letter. On residential schemes, housing land supply can also affect the weight given to development plan policies, and that is worth checking before you decide which forum to use.
When an authority declines
Most authorities validate the application, take the fee, then write to say they are exercising the section 70C power. You get a letter rather than a decision notice. Raise the fee position in your covering email at submission, because an application that never reaches determination sits awkwardly with the fee regulations and practice varies.
Read the letter closely. It should identify the notice, the matters alleged and why the authority considers the application overlaps them. A letter that does none of that is a weaker letter.
Challenging the power
Judicial review in the Planning Court is the formal challenge route, and a claim has to be filed promptly and in any event within six weeks of the decision. Arguable grounds tend to be narrow: no pre-existing notice, an overlap test that was never properly applied, a failure to engage with the differences between the application and the allegation, or an authority applying a blanket policy of declining rather than exercising judgement.
Litigation is rarely the best answer. Writing to the authority setting out why the new scheme differs from the allegation, and asking it to reconsider, costs nothing and sometimes works.
Sequencing after a notice lands
- Read the notice in full: the allegation, the requirements, the compliance period and the date it takes effect.
- Diary the appeal deadline. An appeal must reach the Planning Inspectorate before the notice takes effect, and that date is unforgiving.
- Test immunity against the time limits, and consider a lawful development certificate if the breach predates them.
- Work out whether ground (a) is still available by comparing dates.
- Decide whether to defend what exists or to apply for something materially different.
- Assemble the evidence the route needs, whether that is a parking survey, amenity calculations or policy analysis.
- Keep the compliance period in view. Once a notice takes effect and is not complied with, prosecution under section 179 becomes possible.
This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it, because enforcement timetables are short and the consequences of a missed date are permanent.
If you are preparing the supporting documents for either route, enter your postcode on PlanScope to see which reports the site is likely to need.
PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Can I appeal a decision to decline to determine under section 70C?
No. Declining to determine is not a refusal of planning permission, so there is no right of appeal to the Planning Inspectorate. Judicial review in the Planning Court is the formal challenge route, and a claim must be filed promptly and within six weeks. Writing to the authority to explain why your scheme differs from the allegation usually works better and costs nothing.
Does section 70C apply if no enforcement notice has been issued?
No. The notice must be pre-existing, meaning already issued when the application is made. If you submit a valid retrospective application before any notice is issued, the authority has to determine it. Section 174(2A) may then remove ground (a) from a later enforcement appeal, so you still only get one run at the merits.
Will a smaller or amended scheme get round section 70C?
It can. The power only bites where granting permission would grant permission for the matters specified in the notice. A proposal that is materially different from the allegation, for example a reduced number of bedrooms with added bin and cycle storage, may fall outside it. The authority still decides whether the overlap exists.
Is a retrospective application cheaper than an enforcement appeal?
Not necessarily. An enforcement notice appeal has no appeal fee, but pleading ground (a) triggers a deemed application fee under the fee regulations, and those figures are indexed. Check the current schedule on GOV.UK before assuming one route costs less, and factor in the professional time each option needs.
What happens if I do nothing after a notice is served?
The notice takes effect on the date it states unless an appeal reaches the Planning Inspectorate before then. Once it has taken effect and the compliance period has passed without compliance, the authority can prosecute under section 179 of the 1990 Act and, for some breaches, carry out the works itself and recover the cost.
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.