Single-storey rear extensions, lofts and side extensions you can build in Westminster without full planning — and the exceptions.
Hardly. Westminster holds 3,455 listed buildings, more than any London borough, and its return records no larger home extension decisions at all — not recorded rather than none. It issued 533 lawful development certificates and served 419 enforcement notices, the highest count in London.
| Measure | Westminster | London |
|---|---|---|
| Listed buildings | 3,455 | — |
| Article 4 areas | 10 | — |
| Larger home extension decisions | not recorded | 5,576 |
| Lawful development certificates | 533 | 36,657 |
| Enforcement notices issued | 419 | — |
| Decided within 8 weeks | 74.5% | — |
Sources: MHCLG District Planning Application Statistics (PS1 and PS2), twelve quarters to March 2026; a zero means the measure was not recorded for that borough, never that none exist. Listed building and Article 4 counts from the planning.data.gov.uk designation registers. Open Government Licence v3.0.
In detailSingle-storey rear extension up to 3m deep (attached house) or 4m (detached); side extension up to half the original width; loft conversion up to 40m³ (terraced) or 50m³ (semi-detached); single-storey outbuilding within the curtilage; replacement windows and doors. All subject to material match, eaves setback (20cm), and not facing a highway.
No. Permitted Development rights apply only to houses (Class C3 dwellings). Flats and maisonettes require full planning for almost every external alteration.
Yes — significantly reduced. In a conservation area: side extensions and two-storey rear extensions are not PD; cladding is not PD; chimney removal needs planning; roof additions are restricted.
An LDC is a formal confirmation from the council that your proposal is lawful PD — recommended before building, useful when selling. Costs around £103 for council fees + drawings.
Yes. Building regulations are entirely separate from planning. Permitted Development removes the planning requirement only — you still need building control sign-off for structure, insulation, fire safety, drainage, and ventilation. We deliver both planning and building regs drawings.



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Every Westminster postcode district we draw in, the stock that dominates it and the authority that validates a permitted development scheme there. Westminster fees below are the statutory England rates for 2026, not permitted development scheme estimates.
| Postcode | Area | Dominant stock | What it means for a permitted development scheme |
|---|---|---|---|
| NW1 | Camden Town / Regent's Park | Victorian terraces, mansion blocks | A permitted development scheme in Camden Town / Regent's Park may land with Camden Council or Westminster City Council — NW1 crosses the boundary, and the NW1 policies map decides it street by street. |
| SW7 | South Kensington / Knightsbridge | Stucco terraces, mansion blocks, listed buildings | A permitted development scheme in South Kensington / Knightsbridge may land with RBKC Planning or Westminster City Council — SW7 crosses the boundary, and the SW7 policies map decides it street by street. |
| W1T | Fitzrovia | Georgian terraces, Victorian mansion blocks | Fitzrovia is split at W1T. Either Camden Council or Westminster City Council can determine a permitted development scheme here, so the W1T address is checked against both policies maps first. |
| WC2A | Holborn | Grand Georgian and Regency terraces in Belgravia and Pimlico; Victorian and Edwardian mansion blocks; heritage-rich townhouses throughout; very high listed building density | Holborn is split at WC2A. Either Camden Council or Westminster City Council can determine a permitted development scheme here, so the WC2A address is checked against both policies maps first. |
| NW8 | St John's Wood | Victorian villas, mansion blocks | A permitted development scheme in St John's Wood may land with Westminster City Council or Camden Council — NW8 crosses the boundary, and the NW8 policies map decides it street by street. |
| SW1A | Whitehall / Buckingham Palace | Grand Georgian and Regency terraces in Belgravia and Pimlico; Victorian and Edwardian mansion blocks; heritage-rich townhouses throughout; very high listed building density | Whitehall / Buckingham Palace sits wholly inside SW1A, so Westminster City Council validates every permitted development scheme submitted from an SW1A address. |
| SW1E | Victoria | Regency terraces, post-war flats | Victoria sits wholly inside SW1E, so Westminster City Council validates every permitted development scheme submitted from an SW1E address. |
| SW1H | St James's Park | Grand Georgian and Regency terraces in Belgravia and Pimlico; Victorian and Edwardian mansion blocks; heritage-rich townhouses throughout; very high listed building density | SW1H covers St James's Park only; Westminster City Council handles the permitted development scheme. |
Roof pitch, wall build-up and plot depth change every few Westminster streets, and each one changes what a permitted development scheme can achieve at that address.
How designation changes a Westminster permitted development scheme: Westminster City Council maintains 56 conservation areas, including Marylebone, Pimlico, Soho. Inside any of them a Westminster permitted development scheme cannot rely on permitted development, and the route becomes a £548 householder application determined in 8 weeks rather than a £249 prior approval in 6 weeks. Marylebone sets the tone for Westminster casework.
What Article 4 removes near Westminster: Multiple Article 4 Directions — office-to-residential restrictions, HMO conversions, retail to residential in shopping zones. Before pricing a permitted development scheme we check whether the NW8 address is inside the mapped area, because Westminster City Council draws the Westminster boundary street by street rather than across the whole of Westminster.
Westminster below-ground policy: Westminster basement policy restricts to single-storey, typically under 50% of rear garden footprint; lightwells and rooflights strictly controlled in conservation areas. Any permitted development scheme in Westminster that goes below existing foundations triggers two months notice under section 6 of the Party Wall etc. Act 1996, and Westminster City Council will want the NW8 ground and groundwater position set out.
Westminster housing stock: Grand Georgian and Regency terraces in Belgravia and Pimlico; Victorian and Edwardian mansion blocks; heritage-rich townhouses throughout; very high listed building density. Heritage-first planning approach; listed buildings on almost every street; basement and rear extension policies particularly strict. Read that before choosing a permitted development scheme route in Westminster — construction, not postcode, sets what is achievable.
Sources for this Westminster permitted development scheme page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.

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