HA7 · Stanmore
HA7 is Stanmore — the Stanmore Hill, Old Church Lane and Little Common conservation areas and the Grimsdyke Estate on the wooded ridge. Larger detached and semi-detached plots support extensions under permitted development, with conservation designation the main constraint on prominent work.
Location data: postcodes.io · Constraints: planning.data.gov.uk (borough-level) · Open Government Licence
Constraint context · Harrow
Real · planning.data.gov.ukHarrow has 27 designated conservation areas and 0 Article 4 areas. A district is too coarse to say which apply to your house — postcode districts span many streets and HA7 crosses 4 boroughs. Enter a full postcode below for the point-level check, or read the full borough picture on the Harrow planning guide.
Is HA7 in a conservation area?
Partly — and which part matters. A postcode district is never uniformly designated: HA7 contains 3 conservation areas within 1km of its centre, and whether your own property sits inside one decides whether permitted development survives. The centre point of HA7 itself does not fall inside one — but many of its streets will.
| Canons Park Estate Conservation Area | Nearby |
| Old Church Lane Conservation Area Stanmore | Nearby |
| Stanmore Hill Conservation Area | Nearby |
Conservation areas whose official geometry lies within 1km of the centre of HA7. Source: planning.data.gov.uk · Open Government Licence. Proximity to the district centre is not a statement about your own address — run the address check for that.
Does an Article 4 direction apply in HA7?
The national dataset holds no Article 4 geometry within 1km of the centre of HA7. Treat that as unknown, not as “none”. The national dataset is known to omit property-specific directions, so the only safe answer is to verify on the council's own register for Harrow before assuming a permitted-development right still exists.
Every designation in the borough: Harrow planning guide →
Do you need planning permission in HA7?
Three routes exist, and which one you are on is decided by your address, not your postcode district:
| Permitted development — no application. The work stays inside the GPDO limits and no designation removes them. A Lawful Development Certificate is cheap proof for a future buyer. | No permission |
| Prior approval — the larger single-storey rear extension route, with neighbour consultation. Not available on designated land. | 42 days |
| Full householder application — required once a designation removes your permitted-development right, or the scheme exceeds the limits. | 8 weeks |
HA7 contains mapped conservation-area or Article 4 geometry, so a meaningful share of its streets will have lost some permitted-development rights — which pushes those properties onto the full-application route. Whether yours is one of them is an address-level question, not a district-level one.
What does planning permission cost in HA7?
| Householder planning application | £548 (from 1 April 2026) |
| Lawful Development Certificate — proposed works | £274 (half the application fee) |
| Lawful Development Certificate — existing works | £548 (the full application fee) |
| Listed building consent | No fee |
| Resubmission after a refusal | Free once, within 12 months of the decision |
National statutory figures for England — councils do not set them, so they are the same in every borough. Planning fees re-index every 1 April; confirm the current amount on the Planning Portal fee calculator before you apply. These are the council's fees only — drawings, surveys and any specialist reports are separate.
How long does it take?
| Householder application — statutory target | 8 weeks |
| Householder application — in practice | 8–12 weeks |
| Prior approval (larger home extension) | 42 days |
| Lawful Development Certificate | 8 weeks |
| Householder appeal — deadline to lodge | 12 weeks from the decision date |
| Householder appeal — typical decision | Around 18 weeks |
What if it's refused?
A refusal is a decision notice with reasons attached, and those reasons are a roadmap. Most homeowners in Harrow — as anywhere in England — are better served by amending the scheme and using the free resubmission than by appealing: you get one further application on the same site within 12 months without paying again.
| Who can appeal | The applicant only — not neighbours |
| Fee to appeal | None — you bear your own costs |
| Procedure | Written representations for most householder appeals |
| Success rate | Roughly a third — about 36% of householder appeals allowed in 2025/26 |
Appeals go to the Planning Inspectorate, an independent national body. How to read a refusal and choose your route →
Planning permission by project in Harrow
Interwar semis in Pinner, Stanmore and Kenton extend routinely under PD; the Harrow on the Hill and Pinner conservation areas need a full application.
Rear extension in Harrow →Workable on the Edwardian terraces of Harrow and Wealdstone; the hilltop and Pinner conservation areas need a full application.
Side return extension in Harrow →Strong on the interwar semis of Pinner, Stanmore and Kenton under PD; the Harrow on the Hill and Pinner conservation areas scrutinise dormer design.
Loft conversion in Harrow →Uncommon on the borough's generous-plot stock; a full application with structural and ground-condition evidence is expected, more so in the conservation areas.
Basement extension in Harrow →Large suburban gardens in Pinner, Stanmore and Harrow Weald suit garden rooms under PD; the conservation areas can remove outbuilding rights — check the address.
Garden room in Harrow →Pinpoint your street
More of Harrow
Harrow on the Hill heritage and Metro-land suburbs; conservation-area Article 4 control.
Borough page →Planning Permission Checker provides planning and cost intelligence for early feasibility only. It is not legal, planning, valuation, architectural, structural, or surveying advice. All estimates are indicative and must be verified by qualified professionals before purchase, design, planning submission, or construction.
Cost estimates are indicative only — not a quotation. Final price depends on survey, specification, structure, access, party wall matters, VAT, professional fees, and contractor availability.
Planning outcomes are not guaranteed. Local planning authorities make final decisions.