Permitted Development Rights in London: What You Can Build Without Planning Permission

Permitted development (PD) rights are a category of pre-approved planning permission granted by the government, allowing homeowners to carry out certain types of work without submitting a planning application to the local authority. In theory, they simplify and speed up common home improvements. In practice — particularly in London, and particularly in the prime central boroughs — their application is significantly more limited than many clients expect.

This guide sets out what permitted development rights allow, where they do not apply, and what the process looks like for confirming whether works are permitted.

What permitted development rights cover

For a standard residential property in England, permitted development rights allow (subject to conditions):

Rear extensions

A single-storey rear extension up to 4 metres deep for a detached house, or 3 metres deep for any other house, without planning permission — provided the extension does not exceed 4 metres in height and is not forward of the principal elevation.

Under the Neighbour Consultation Scheme (often called the Prior Approval process), these limits can be extended to 8 metres for detached houses and 6 metres for others, subject to a consultation with neighbouring properties.

Loft conversions

A loft conversion that adds up to 40 cubic metres of additional roof space for a terraced house, or 50 cubic metres for a detached or semi-detached house, is permitted development — provided it does not extend beyond the plane of the existing roof slope facing the highway, is not higher than the highest part of the existing roof, and uses materials that match the existing house.

Side extensions

A single-storey side extension up to half the width of the original house, not exceeding 4 metres in height, is permitted for detached and semi-detached houses — but not for terraced houses, where side extensions require planning permission.

Outbuildings

Outbuildings (including garden rooms, garages, and sheds) within the curtilage of the house are permitted provided they do not exceed a certain height and do not cover more than half the garden area. They must be used for purposes incidental to the enjoyment of the house and not as separate living accommodation.

Internal works

Most internal works — removing internal walls, reconfiguring rooms, adding a bathroom — do not require planning permission regardless of PD status. They may, however, require building regulations approval. This is a common point of confusion: planning and building regulations are separate regimes. See our guide on planning permission vs building regulations for clarity.

Why permitted development is restricted in much of London

For a significant proportion of prime London properties, standard permitted development rights are either restricted or entirely removed. The main reasons are:

Conservation areas

Properties within designated conservation areas lose many of their standard PD rights. In a conservation area:

• —Side extensions require planning permission
• —Cladding the exterior of the house in stone, artificial stone, pebble dash, render, timber, plastic, or tiles requires planning permission
• —Satellite dishes on the front or side of a house require planning permission
• —Demolition of outbuildings over a certain size requires planning permission

Conservation areas cover a very high proportion of the prime London residential market. Kensington, Chelsea, Belgravia, Mayfair, Notting Hill, Islington, and large parts of Camden and Hammersmith are substantially or entirely within conservation areas. See our conservation area renovation guide for detail.

Article 4 Directions

An Article 4 Direction is a mechanism by which a local planning authority removes specified PD rights from an area or property type. They are commonly used in London conservation areas to restrict even the most minor external changes — repainting in a non-standard colour, replacing windows with non-matching units — that would otherwise not require permission.

Article 4 Directions must be checked area by area. The relevant borough's planning portal will confirm which directions apply in a given postcode.

Listed buildings

Listed buildings have no permitted development rights. Every alteration that affects the special architectural or historic interest of a listed building — including many internal works — requires listed building consent in addition to any planning permission that may be needed. This applies regardless of whether the property is Grade I, Grade II*, or Grade II listed.

See our listed building renovation guide for a full account of what listed building consent covers and requires.

Flats and maisonettes

Permitted development rights do not apply to flats or maisonettes. If you own a flat — including a flat within a converted period townhouse — essentially all external works and many internal structural changes require planning permission or consent from the freeholder, or both.

This is a particularly important point for the prime London market, where a high proportion of properties are converted flats rather than whole houses.

The Lawful Development Certificate

Even where works are genuinely permitted development — no planning permission needed — there is a strong practical argument for obtaining a Lawful Development Certificate (LDC) from the local planning authority before or after the works.

An LDC is a formal confirmation from the council that the works described are lawful. It provides:

• —Certainty for the owner and their contractor that the works can proceed
• —Protection against enforcement action if questions arise later
• —A document for the property file that demonstrates lawfulness to future buyers and their solicitors

The application fee for an LDC is around £100–250. The process typically takes 6–8 weeks. It is not a legal requirement, but for any works of significance, it is worth doing.

Without an LDC, a dispute about whether works were lawful may arise years later — typically when the property is sold — and without it there is no straightforward way to prove legality beyond the owner's recollection and the planning history.

Prior Approval

For extensions beyond the standard PD limits — the larger rear extensions available under the Neighbour Consultation Scheme — the process requires Prior Approval from the local planning authority. This is not a full planning application, but it does require:

• —Notification to the council of the proposed works
• —A consultation period during which neighbouring owners can raise objections
• —Assessment by the council of whether the works meet the Prior Approval criteria (principally: impact on the amenity of neighbouring properties)

If the council receives no objections and is satisfied on the criteria, it issues a Prior Approval. The assessment is limited — Prior Approval is not a full planning assessment — but it does give neighbouring owners a formal opportunity to object, and councils do refuse Prior Approval where the evidence of harm to neighbours is clear.

Checking PD status: the practical approach

Given the complexity of the restrictions that apply in prime London, the safest approach to any proposed works is to establish clearly, before committing to a design, whether planning permission is required. The steps are:

1. 1.Confirm whether the property is listed (Historic England's Listed Buildings register, or the local authority's planning portal)
2. 2.Confirm whether it is in a conservation area (local authority planning portal, searchable by address)
3. 3.Check for Article 4 Directions in the relevant area (local authority planning portal)
4. 4.Review the specific PD rights applicable to the property type (house vs flat; detached vs terrace)
5. 5.If the works appear to be PD, consider applying for a Lawful Development Certificate before starting

For any uncertainty, or for works that are close to the PD limits, pre-application advice from the local planning authority is the most reliable way to confirm the position.

ASAAN's project teams check planning status at the earliest stage of every project. If you are unsure whether a proposed renovation requires planning permission, contact us and we can guide you through the relevant checks or connect you with a planning consultant.