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Greater London

Planning permission in London

What homeowners in London need to know about planning permission before starting an extension, loft conversion or major renovation in Greater London.

Local context — London

Council
Varies by borough (32 boroughs + City of London)
Open planning portal →
Cost premium
+18-25% vs UK average (inner London) / +8-15% (outer boroughs)
Typical extension price
A 25 m² rear extension in London typically runs £78,000-£125,000 (standard to luxury, 2026). Side-return extensions in Victorian terraces (Clapham, Islington, Hackney) cluster at £85-110k for a standard spec.
Building Control
Every London borough has its own Building Control; most homeowners use private Approved Inspectors (LABC, BBS, Stroma) for faster turnaround. Inspection lead time is 1-3 working days across most boroughs.
Conservation & Article 4
London has 1,000+ conservation areas. Article 4 directions are extensive across Camden, Hackney, Islington, Kensington & Chelsea and Westminster — assume PD rights are removed in any pre-1940 street until the borough confirms otherwise.
Local quirks that move the price
Parking suspensions (£40-110/day depending on borough) and CPZ dispensations are mandatory on most builds. Party-wall agreements typically needed on both sides for terraces. London Plan policy now requires sustainable urban drainage (SUDS) on most extensions over 5 m² of new hard surface.
High-demand areas in London
ClaphamIslingtonHackneyWandsworthLewishamEaling

When you need planning permission in London

Most single-storey rear extensions in London fall under Permitted Development (PD), provided they stay within size, height and material limits. Two-storey extensions, side-return extensions on terraces, and any work in a conservation area or to a listed building typically require a full planning application from your local authority in Greater London.

Permitted Development limits used in London

For detached homes, rear extensions can usually go up to 8 m deep (single-storey) without planning. For terraced and semi-detached, the limit is 6 m. Maximum eaves height is 3 m within 2 m of the boundary, and side extensions must be single-storey, no more than 4 m high, and no wider than half the original house. Always file a Prior Approval / Lawful Development Certificate to lock the rights in writing.

Conservation areas and listed buildings

London has several conservation areas where Permitted Development rights are restricted or removed entirely (Article 4 directions). Listed buildings always require Listed Building Consent in addition to planning. Check the local authority's planning portal before quoting builders.

Typical timelines & fees

A householder planning application takes 8 weeks for a decision. Fees are £258 for England householder applications (2026). Lawful Development Certificates cost £129. Budget 4–6 weeks extra for drawings and pre-application advice if needed.

Get the London planning permission checklist

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FAQs about planning permission in London

Do I need planning permission for a loft conversion in London?

Most rear dormer loft conversions in London are Permitted Development if the dormer is under 40 m³ (terraced) or 50 m³ (semi/detached) and doesn't sit on the front roof slope. Mansard conversions and anything in a conservation area need full planning.

How much does a planning consultant cost in London?

Typical fees are £600–£1,800 for a householder application including drawings. Pre-application advice from the council adds £150–£400 but often saves weeks on contentious schemes.

Can my builder submit the planning application?

Usually no — you need a designer or architect to prepare scaled drawings and the application. Some builders have an in-house designer, but the application is filed in the homeowner's name.

More London guides

Build timeline in LondonVetting builders in LondonSave on renovation in London

Planning permission in other UK cities

CroydonEalingEnfieldBromleyBarnetWandsworth

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