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Borough Comparison · 2026

Planning Permission in South London (2026 Guide): Lambeth vs Wandsworth vs Southwark

The same rear extension can sail through in Wandsworth, face design scrutiny in Lambeth, and meet a policy-heavy review in Southwark. This guide explains exactly what homeowners in each borough can expect in 2026 — and the hidden factors that decide most outcomes.

Lambeth, Wandsworth, and Southwark share borders and housing stock but operate meaningfully different planning cultures. This guide explains why — and what it means for your specific project in 2026.

Check your property All borough guides

Borough Guide

Wandsworth

Full Wandsworth guide

Battersea, Balham, Tooting, Putney, Clapham South

Wandsworth is widely regarded as one of the most pragmatic planning authorities in London. It has a consistently pro-development stance backed by clear, well-signposted local policy. Officers are generally willing to engage, and the council's track record on householder applications is stronger than almost any inner-London borough.

What works well in Wandsworth

Rear and side return extensions on Victorian terraces — a standard Wandsworth application type with a high approval rate when policy is followed

Loft conversions with dormers — including rear dormers on houses not in Conservation Areas, where Wandsworth applies guidance consistently rather than subjectively

Basement extensions — permitted in principle, though the council has tightened its basement SPD following structural concerns. A structural impact assessment and drainage strategy are required

Side extensions — single storey, within the 50% width limit, generally well-received where no adverse neighbour impact

Key constraints in Wandsworth

Conservation Areas in parts of Battersea, Wandsworth Town, and Putney — these remove PD rights for dormers and side extensions and require full applications with greater design justification

Basement scrutiny has increased since 2022 — while not banned, deeper or complex basements face longer decision times and more conditions than in previous years

Party wall issues are common in the borough's dense terrace streets — not a planning matter, but failure to serve notice can delay construction significantly

Approval insight: Standard residential extensions following Wandsworth's design guidance have a high approval rate. The borough rewards well-prepared applications and clear policy compliance. Unusual or oversized designs are less likely to face an outright refusal here than in neighbouring boroughs — officers tend to negotiate rather than refuse.

See the full Wandsworth planning guide

Borough Guide

Lambeth

Full Lambeth guide

Clapham, Brixton, Streatham, Stockwell, Herne Hill, West Norwood

Lambeth has shifted in recent years toward a more housing-positive position, driven by significant borough-wide housing targets. The council is broadly supportive of well-designed residential development. However, its planners apply genuine design scrutiny — particularly in Conservation Areas and across the dense Victorian terraces of Clapham and Brixton — and poorly designed or incongruous extensions face a meaningful refusal risk.

What works well in Lambeth

Rear extensions that respect the building line, use matching or complementary materials, and avoid excessive overlooking of neighbours

Loft conversions with modest rear dormers — Lambeth is less restrictive than Southwark on dormers in non-Conservation Area streets, provided the roof form is not dominated by the addition

New basement levels in larger properties, particularly in Streatham and Herne Hill, where plot sizes allow proper natural light and ventilation

Proposals near Brixton, Stockwell, and Clapham North transport hubs — the council's Local Plan supports higher-density development within walking distance of major stations

Key constraints in Lambeth

Conservation Areas are extensive in Lambeth — Clapham Old Town, Clapham Common, Brixton Market, and others impose significant controls on external alterations

Daylight and sunlight impact is taken seriously by Lambeth planners — extensions that cause measurable loss of light to habitable rooms in adjacent properties are a frequent reason for refusal or conditioning

Design must respond to local character, not just meet dimensional thresholds — Lambeth planners are vocal about incongruous materials, inappropriate roof forms, and extensions that dominate the host building

Overlooking and privacy — rear extensions in tight terraces require careful attention to window positioning to avoid objections and conditions

Approval insight: Lambeth rewards applications that take design seriously. A well-prepared scheme with a design-and-access statement that engages with local character will fare significantly better than a template application. Pre-application advice is available and genuinely useful in Lambeth — particularly for Conservation Area proposals or anything involving basement or roof work.

See the full Lambeth planning guide

Borough Guide

Southwark

Full Southwark guide

Dulwich, Peckham, Bermondsey, Borough, Canada Water, Forest Hill

Southwark operates one of the more rigorous planning regimes among inner-London boroughs. Its Local Plan, Residential Design Standards SPD, and Conservation Area appraisals are detailed documents that officers apply carefully. The council also has a higher-than-average rate of applying conditions and has been known to refuse applications that would be approved in neighbouring boroughs — particularly where environmental performance or neighbour impact is borderline.

What works well in Southwark

Carefully designed extensions in non-Conservation Area streets that clearly meet Southwark's Residential Design Standards — the council rewards thorough applications

Loft conversions on larger houses in Dulwich and Forest Hill where roof space is generous and dormer size is proportionate — Southwark's SPD gives clear guidance on acceptable dormer dimensions

Proposals that improve energy efficiency performance, particularly those meeting or exceeding Part L requirements — Southwark has been an early adopter of sustainability conditions

Rear extensions on properties in Peckham and Bermondsey where the surrounding development context already includes similar additions and precedent is well-established

Key constraints in Southwark

Article 4 Directions are in force across parts of Southwark, particularly in Conservation Areas and residential streets where the council wants to prevent HMO conversions or maintain frontage character

Dulwich Conservation Area is one of the most strictly managed in South London — the Dulwich Estate exercises additional private covenant controls on top of council planning controls, which can restrict works even where planning permission is not formally required

Height and massing restrictions are applied firmly — Southwark's SPD specifies storey heights and roof-to-wall proportions that officers enforce with less room for negotiation than Wandsworth

Environmental standards — Southwark applies conditions requiring compliance with its sustainability checklist on all major applications and increasingly on householder work

Longer decision times — Southwark frequently uses the full 8-week statutory determination period and has a higher rate of seeking extensions of time than neighbouring boroughs

Approval insight: Southwark is not impossible — but it requires a higher level of preparation. Applications should engage directly with the Residential Design Standards SPD and, where applicable, the relevant Conservation Area appraisal. Pre-application advice is strongly recommended for anything beyond a straightforward small extension. A planning consultant alongside an architect is worth serious consideration for higher-value or complex schemes.

See the full Southwark planning guide

Often overlooked

The hidden factors that decide most outcomes

Across all three boroughs, the difference between approval and refusal often comes down to factors that aren't covered in the standard planning guidance — and that most homeowners don't discover until after a rejection.

Nearby planning precedent

All three councils look at what has been approved (or refused) on comparable properties in the same street or area. A recently approved dormer two doors away is a meaningful material consideration. Our tool surfaces this precedent data automatically for your address.

Design quality as a material consideration

Especially in Lambeth and Southwark, an extension that meets every dimensional threshold can still be refused on design grounds. The quality and justification of your architect's design statement matters — this is where an experienced local architect earns their fee.

Pre-application advice

All three boroughs offer a pre-application advice service (for a fee — typically £200–£600 for a householder scheme). In Southwark and Lambeth, this is often money well spent: a planning officer's written response before submission gives you a roadmap for the formal application and significantly reduces refusal risk.

Planning history of your specific property

If previous applications have been refused at your address — by you or a previous owner — officers will be aware and may scrutinise a new application more carefully. Conversely, if a similar extension was approved next door, that creates a strong positive precedent.

FAQ

Questions South London homeowners ask

Which South London borough is easiest for planning permission?

Wandsworth is consistently regarded as the most pragmatic and development-friendly of the three. Its officers apply policy consistently, engage constructively with applicants, and have a strong approval rate for well-prepared householder applications. Lambeth sits in the middle — more design-focused but broadly supportive of growth. Southwark applies the most rigorous policy review and has the highest refusal rate for marginal schemes.

Do I need planning permission for a rear extension in Lambeth, Wandsworth, or Southwark?

It depends on your property type, the extension dimensions, and whether your address is in a Conservation Area or covered by an Article 4 Direction. A single-storey rear extension within 3m depth (terraced/semi) or 4m depth (detached) is usually Permitted Development for houses — but only where PD rights haven't been removed. Southwark has Article 4 Directions in some areas; Lambeth and Wandsworth both have Conservation Areas that restrict PD. Always check your specific address before starting work.

Is Dulwich particularly difficult for planning permission?

Yes. Dulwich sits within Southwark (one of the more restrictive boroughs) and is covered by an extensive Conservation Area. Many Dulwich properties are also subject to Dulwich Estate covenants — private legal controls that restrict alterations independently of planning permission. Any project in Dulwich should factor in both planning and covenant checks before appointing an architect.

Should I use a planning consultant in these boroughs?

In Wandsworth, a good architect with local experience is usually sufficient for a standard householder application. In Lambeth, a planning consultant is worthwhile for Conservation Area schemes or anything involving basement or significant roof work. In Southwark, a planning consultant alongside your architect is strongly recommended for any project valued over £50,000 or any scheme that sits at all close to a policy boundary — the council's detailed SPD makes professional interpretation of policy a genuine advantage.

Next step

Check your specific property before paying for drawings

Borough-level guidance tells you the general picture. Our tool tells you what applies to your specific address — Conservation Area status, Article 4 coverage, nearby approved applications, and a planning feasibility assessment for your project type.

Start a planning check All borough guides