Planning Permission for a New Dwelling in London 2025: What You Need to Know

New dwelling development in London covers a wide range of project types. The most common types relevant to homeowners, small developers, and design-and-build contractors in London: Infill development (constructing a new house or flat on a vacant plot within an established residential area — a gap site between existing properties, a former commercial or industrial site in a residential area, or a previously developed brownfield site): planning applications for infill residential development in London are assessed against: the borough's local plan policies for residential development and housing; the London Plan (particularly Policy H2 — Small Sites and self-build; Policy HC1 — heritage and conservation; Policy D1 — London's design principles; Policy D3 — optimising site capacity; Policy D6 — housing density); NPPF Chapter 5 (delivering a sufficient supply of homes) and Chapter 12 (achieving well-designed places); SPGs, SPDs, and design guides (Supplementary Planning Guidance documents — e.g., the London Housing Design Guide, borough-specific residential design guides, residential design SPDs). Key considerations for infill development in London: density — the London Plan's density matrix (Policy D3) encourages optimising site capacity based on public transport accessibility level (PTAL rating) and the local context. In high-PTAL inner London areas (PTAL 5-6), higher densities are generally acceptable. In low-PTAL outer London suburban areas (PTAL 1-2), lower densities are expected. Design — new dwellings in London are expected to demonstrate good design quality (design champion has become a standard requirement in most inner London boroughs). Many boroughs require a Design and Access Statement for all new dwelling applications — explaining how the design has been developed to respond to the local context, character, and urban grain. Parking — most inner London boroughs apply car-free or car-lite standards for new residential development (no off-street parking required in high-PTAL areas); outer London borrows typically require minimum parking provision. Garden development (constructing a new house or flat in the garden of an existing residential property — garden infill): planning permission is required for any new dwelling, and the application is assessed against the same policies as any residential infill development. However: loss of garden space is a material planning consideration in many London boroughs — particularly where the borough's local plan has policies protecting residential garden areas from development (for example, Policies preventing development on residential garden land in areas of low housing density or suburban character). 'Garden grabbing' is a common concern raised by planning officers and neighbours in London — the garden of a house is typically a private green space making an important contribution to the character of the area, to biodiversity, and to drainage. Subdivision of an existing dwelling (converting a single house into two or more flats, or subdividing a large house into a house and a studio or annexe): planning permission is required for a change of use from a single dwelling (C3a) to two or more dwellings (C3a — conversion from house to flats, or house to HMO class C4 where more than 6 unrelated residents). An important London-specific restriction: many London boroughs have local plan policies PROTECTING existing family houses from conversion to flats, particularly in outer London suburban areas — on the grounds that the loss of family housing is contrary to the borough's housing strategy. A conversion of a 4-bedroom house to two 2-bedroom flats may be refused in an area where the local plan policy protects existing family housing stock, even if the converted flats would satisfy other planning criteria. Always check the borough's local plan policies on housing subdivision before committing to a conversion strategy. Replacement dwelling (demolishing an existing house and constructing a new, larger house on the same plot): planning permission is required for the demolition of a dwelling (Conservation Area Consent or prior approval for demolition) and for the new build. Replacement dwellings in London suburban areas are commonly refused where: the new dwelling is significantly larger in volume and footprint than the existing (overdevelopment); the new dwelling is out of character with the neighbouring properties; the loss of the existing building (particularly in a conservation area) is not justified by the quality of the replacement. New build on a purpose-built residential development site (a developer-led new residential development of multiple dwellings): this is subject to all of the above policies, plus: affordable housing requirements (typically triggered at 10 dwellings or 1,000 sq m of residential floorspace in most London boroughs — the exact threshold varies); the GLA's strategic planning oversight (the Mayor of London is a statutory consultee for major applications, defined in the London Plan — typically applications for 10 or more residential units, or 1,000 sq m or more of floorspace).

Community Infrastructure Levy (CIL) for new dwellings in London: CIL is a mandatory charge levied by the local planning authority (and by the Mayor of London — the Mayoral CIL) on new residential floorspace created by development. It is charged per square metre of new floorspace and must be paid before development commences. Mayoral CIL (MCIL2): the Mayor of London's CIL applies across Greater London to fund Crossrail 2 and other strategic transport infrastructure. MCIL2 rate: £80 per sq m of new residential floorspace (as at 2024 — this rate has not been updated since April 2019 and may be subject to future review). Borough CIL: in addition to MCIL2, most London boroughs have their own borough CIL charging schedule. Borough CIL rates vary significantly across London: nil CIL boroughs (some outer London boroughs charge nil borough CIL — e.g., Havering, Barking and Dagenham); mid-range CIL boroughs: many London boroughs charge approximately £50-£300 per sq m; high CIL boroughs (central and inner London): some inner London boroughs charge significantly higher rates — for example, the London Borough of Wandsworth charges up to £850 per sq m in some zones; Kensington and Chelsea and Westminster can charge £600-£1,000+ per sq m in some zones. CIL exemptions for new dwellings in London: self-build exemption: a self-build dwelling (where the owner-occupier is building for their own use, not for sale or rental) is exempt from both MCIL2 and borough CIL. CRITICAL: the self-build CIL exemption must be applied for and GRANTED by the planning authority BEFORE commencement of development — if development commences before the exemption is granted, the exemption is lost and CIL becomes immediately payable (in full, plus surcharge). Social housing relief: affordable housing units provided as part of a development are exempt from CIL. Charitable relief: development by charities for their charitable purposes may be exempt. Minor development exemption: development of fewer than 100 sq m of new floorspace that does not create a new dwelling is exempt from CIL. Affordable housing requirements for new dwellings in London: London Plan Policy H6 (Threshold approach to applications) sets the framework for affordable housing requirements in London. The current London Plan (2021) requires: developments of 10 or more homes, or on sites of 0.25 hectares or more (the 'threshold' for affordable housing obligations): 35% affordable housing by habitable room (or 50% where the public land contribution or Homes England support can make this viable). Fast track route: developments that provide at least 35% affordable housing (without public subsidy) and where the affordable housing is at least 30% London Affordable Rent, 30% intermediate (shared ownership or other intermediate tenure), and the remainder of the 35% in any combination, proceed on a fast track without a viability assessment. Developments below the 10-home threshold: in most London boroughs, applications for fewer than 10 homes (or fewer than the borough's specified threshold) are assessed under the borough's local plan policies rather than the London Plan threshold approach. Small residential developments in London (1-9 dwellings) may still be subject to affordable housing contributions (a financial contribution in lieu of on-site affordable housing) under some borough local plans — check the specific borough's affordable housing policy. S106 agreements for smaller London residential developments: where a planning application for a new residential development is agreed subject to a Section 106 (S106) legal agreement, the S106 may include: affordable housing financial contribution (in lieu of on-site units); CIL in lieu (where not covered by the standard CIL charging schedule); infrastructure contributions (highways, parks, open space, health, education); restrictions on occupation (parking restrictions, car-free condition); planning obligations (public realm, landscaping, biodiversity net gain).

The Mayor of London is a statutory planning authority for Greater London under the Greater London Authority Act 1999 and the Planning Act 2008. The GLA exercises its planning powers through: The London Plan: the Mayor's statutory spatial development strategy for Greater London — a development plan document that all London boroughs must take into account in their own local plans and when determining planning applications. The current London Plan was adopted in March 2021. The Mayor of London as a statutory consultee on major planning applications: the Mayor must be consulted (and has the power to direct refusal or call in) major planning applications in London, defined in the Town and Country Planning (Mayor of London) Order 2008 as: applications for 150 or more residential units; applications for development creating 15,000 sq m or more of non-residential floorspace; applications in the Thames Policy Area, the Lee Valley Regional Park, or other strategic locations; applications for development that is likely to have strategic significance for London. For most homeowners and small developers in London (building a single new dwelling, converting a house, or building a small residential development of fewer than 10 units), the GLA is not directly involved in the planning decision — the London borough determines the application. The GLA becomes relevant when: the proposed development is for 10 or more residential units (the threshold for the London Plan's fast track affordable housing route and the threshold for GLA strategic consultation); the site is in the Thames Policy Area (TPA — stretching approximately 1km back from the Thames in most locations) or another GLA strategic location; the proposed building height exceeds the local plan's maximum height in the area (London-wide tall buildings policies apply). GLA pre-application services: the GLA offers pre-application advice (GLA PAD) for major applications. Applications for 10 or more residential units are encouraged to seek GLA PAD before the formal application stage. GLA PAD service: fee-based, typically £2,000-£5,000 for a small major application. Biodiversity Net Gain (BNG) for new dwellings in London: from April 2024, all major planning applications in England (including major residential applications in London) are subject to the mandatory Biodiversity Net Gain requirement under Schedule 14 of the Environment Act 2021. BNG requires developments to deliver at least 10% net gain in biodiversity value (measured using the Natural England biodiversity metric) compared to the pre-development baseline. For minor applications (fewer than 10 dwellings and under 0.5 hectares): mandatory BNG from April 2024. For householder applications (extensions and alterations to existing dwellings): exempt from mandatory BNG. BNG assessment: the applicant must commission a Biodiversity Net Gain assessment (using Natural England's Biodiversity Metric 4.0 or current version) as part of the planning application. Where BNG cannot be achieved on site: BNG credits can be purchased from statutory BNG credit scheme (Natural England) or from off-site BNG providers. BNG cost for a small residential development: variable depending on site baseline and development impact — typically £2,000-£20,000+ for the assessment and any off-site credits required.