Planning Rules
Prior Approval: What It Is, When You Need It, and How to Apply (2025)
Prior Approval sits between full permitted development and a planning application. You notify the council of your intention to build — but they can only consider certain matters, not refuse on general planning grounds.
⏱ 6 min read📅 Updated June 2025🏠 England only
Quick Answer
A limited form of consent — the council cannot refuse on general planning grounds
Prior Approval is a consent process required for certain types of permitted development — mainly larger extensions, agricultural conversions (Class Q), office-to-residential conversions (Class MA), and other Part 3 changes of use. The council has a fixed period (typically 42 or 56 days) to determine whether Prior Approval is required and, if so, to grant or refuse it. Critically, the council can only assess specified matters — transport, flooding, contamination, design (for some classes), etc. It cannot refuse on general planning policy grounds. If the council fails to respond within the determination period, Prior Approval is deemed granted.
What Is Prior Approval?
Prior Approval is a lighter-touch consent mechanism written into certain PD classes in the GPDO 2015. It was introduced to balance the speed and certainty of permitted development with the ability for local authorities to assess specific impacts where they might be significant.
Prior Approval is not planning permission — it doesn’t go through the full planning application process, isn’t assessed against the development plan, and can’t be refused on general amenity or policy grounds. It’s a targeted check on specific issues the government has decided are worth reviewing for that particular type of development.
When Is Prior Approval Required?
Prior Approval is required for several common PD categories:
| Development type |
PD Class |
Determination period |
| Larger home extension (single-storey rear, 4–8m detached / 3–6m other) |
Part 1 Class A |
42 days |
| Agricultural building to dwelling |
Part 3 Class Q |
56 days |
| Commercial/office to residential (Class MA) |
Part 3 Class MA |
56 days |
| Agricultural to flexible commercial use |
Part 3 Class R |
56 days |
| Demolition and rebuild (Class ZA) |
Part 20 Class ZA |
56 days |
| Upward extensions (mansard / additional storeys) |
Part 20 Classes A–AC |
56 days |
How to Apply
Prior Approval applications are submitted to the local planning authority — either through the Planning Portal or the council’s own system. The application requires:
- A completed application form
- A written description of the proposed development
- A site location plan
- Any drawings or information relevant to the specified matters the council must consider
- The applicable fee (varies by class — larger home extension is £120 per dwelling; Class Q is £96 per dwelling)
The council then decides: (1) whether Prior Approval is required at all; (2) if required, whether to grant or refuse it having considered only the specified matters. If Prior Approval is not required, the development can proceed immediately. If the council fails to respond within the determination period, Prior Approval is deemed granted.
⚠️ The 42/56-day clock starts from a valid application The determination clock starts when the council acknowledges the application as valid — not when you submit it. If the council requests additional information, the clock may be paused. Ensure you submit all required documents with the initial application to avoid delays.
What the Council Can Consider
The matters the council can consider vary by PD class, but common assessment criteria include:
- Transport and highways: Impact on the local road network and parking
- Contamination: Whether the site may be contaminated and risk to future occupants
- Flooding: Whether the site is at risk of flooding
- Noise: Noise impacts from neighbouring uses on future occupants
- Design and external appearance: Applies to some classes (Class Q, Class MA) but not others (larger home extension)
- Impact on amenity of neighbouring properties: For larger home extensions, neighbouring properties are consulted and can object
✅ The council cannot consider general planning policy A refusal of Prior Approval must be based on one of the specified matters. The council cannot refuse because it thinks the development is ugly, contrary to the development plan, or contrary to housing policies. This is the key advantage of Prior Approval over a planning application.
Frequently Asked Questions
What happens if the council doesn’t respond to a Prior Approval application in time?
If the council fails to notify you of their decision within the statutory determination period (42 days for larger home extensions, 56 days for most other classes), Prior Approval is deemed to have been granted. You can then proceed with the development. However, you should keep evidence of the submission date and the lack of response, and consider writing to the council to confirm the deemed approval. Start on site only when you’re confident the deemed approval applies.
Can Prior Approval be refused?
Yes — the council can refuse Prior Approval if the development fails on one of the specified matters (transport, flooding, contamination, noise, design, etc.). A refusal can be appealed to the Planning Inspectorate. However, the grounds for refusal are limited — the council cannot refuse on general planning policy grounds, visual impact on the wider area, or other matters outside the specified list.
Is Prior Approval the same as planning permission?
No — Prior Approval is not planning permission. It’s a limited consent process that checks only specified matters for certain types of permitted development. Planning permission is assessed against the full development plan and all material considerations. Prior Approval is faster (typically 42–56 days), cheaper, and the council’s ability to refuse is much more limited than for a planning application.
Do I need Prior Approval for a rear extension?
Only if the extension is larger than the standard PD limits. Single-storey rear extensions up to 4m (detached) or 3m (semi/terraced) do not require Prior Approval — they are automatic permitted development. Extensions between 4–8m (detached) or 3–6m (semi/terraced) require Prior Approval under the larger home extension scheme. The council notifies neighbours and can only refuse on impact to neighbouring amenity.
More on Permitted Development Rights
Extensions, loft conversions, outbuildings, solar panels — our complete guide covers everything you can build without planning permission.
Read the Complete PD Guide →
