How planning permission works in London: a homeowner guide (2026)
Planning a London extension, renovation or conversion often begins with a simple question: do you need planning permission? The answer depends on the work, the type of property and the planning controls that apply to it.
This guide explains how planning permission works in London, when a planning application is commonly required, how borough councils assess proposals, how long the process normally takes and what happens after a decision. It also explains the differences between planning permission, permitted development, Building Regulations and listed building consent.
The guidance is intended as a practical starting point for homeowners. Planning decisions are property-specific, so check the position with your London borough or obtain professional advice before relying on a particular approval route.
If you need advice tailored to your property, GOAStudio’s architectural planning service for London homes covers feasibility, design, drawings, submission and council liaison.
Planning permission in London: at a glance
- Planning permission is normally required for development that falls outside permitted development rights or involves a material change of use.
- Your London borough acts as the Local Planning Authority and decides the application.
- Householder and other non-major applications normally have an eight-week statutory determination period once valid, although applications can take longer.
- Permitted development may allow certain work without a full planning application, subject to detailed limits and conditions.
- Flats and maisonettes do not benefit from the householder permitted development rights that apply to many houses.
- Conservation areas, Article 4 Directions and listed status can introduce additional controls.
- Planning permission and Building Regulations are separate systems, and many projects need both.
GOAStudio London residential architecture
George Omalianakis, BA (Hons) B.Arch Pg Dip Environmental Design.
Chartered RIBA architect and ARB registered.
RIBA Conservation Registrant specialism in conservation areas, period and Listed buildings.
Residential expert contributor for magazines including Which? magazine and Ideal Home.
Last reviewed by George Omalianakis for GOAStudio: August 2026
If you need advice tailored to your property, GOAStudio’s architectural planning service for London homes covers feasibility, design, planning drawings, submission and council liaison.
Feasibility Review
A request a Feasibility Review is often the best first step if you want a realistic view of planning restrictions, design scope and what is worth pursuing before you commit further.
Home Consultation
If you already need more detailed, property-specific advice, Book a home consultation and we can help you clarify the brief, priorities and likely next steps.
Planning permission and other approval routes
Different approvals answer different questions. A project may need more than one, and obtaining one approval does not remove the need for another.
Planning permission
What it deals with: design, scale, appearance, land use, neighbour impact, local character and heritage context.
Who assesses it: your London borough as Local Planning Authority.
Permitted development and Lawful Development Certificates
What they deal with: whether work complies with nationally defined permitted development rights and whether the development is lawful in planning terms.
Who assesses a certificate application: your London borough.
Building Regulations
What they deal with: structure, fire safety, insulation, ventilation, access and other technical construction standards.
Who assesses compliance: local authority Building Control or a registered building control approver, depending on the route used.
Listed building consent
What it deals with: whether work affects the special architectural or historic interest of a listed building.
Who assesses it: the borough’s planning and conservation service.
The London planning application process
The planning application process begins before anything is submitted. Establishing the likely approval route, understanding the property and resolving the design are usually the most important preparatory stages.
1. Check the property and planning context
Start by confirming the property type, planning history, conservation or listed status and whether an Article 4 Direction or planning condition affects permitted development rights. Your borough’s planning map, Local Plan, design guidance and conservation documents may all be relevant.
2. Develop the design
The design should respond to both the homeowner’s brief and the planning context. At this stage it is useful to compare layout options, test extension depth and roof form, consider neighbouring properties and decide which planning route is realistic.
3. Consider pre-application advice where it adds value
Many London boroughs offer paid pre-application advice. It can be helpful for sensitive, unusual or larger proposals, but it is not necessary for every householder project and it does not guarantee approval.
Government guidance describes the pre-application stage as a two-way process intended to provide an early view on the merits of a proposal and the information likely to be required.
4. Prepare the application
A planning application will normally include forms, ownership certificates, the application fee, a site location plan and scaled existing and proposed drawings. Depending on the project, it may also require a design statement, heritage information, tree material, daylight analysis or other specialist reports.
The Planning Portal’s guide to what to submit with a planning application outlines the national application requirements. London boroughs also publish local validation lists.
5. Submission and validation
After submission, the council checks whether the correct forms, fee, drawings and supporting documents have been provided. The statutory determination period starts when the application is valid, not necessarily on the day it was first uploaded.
Once valid, the application is placed on the public planning register and given a reference number. The Planning Portal explains how applications are validated and processed.
6. Consultation and assessment
The council publicises the application and may consult neighbours, internal specialists and statutory consultees. A planning case officer assesses the proposal against policy and the site context. A site visit may take place, but it should not be assumed in every case.
The Planning Portal provides further information on publicity and consultation after validation.
7. Amendments and extensions of time
A case officer may request clarification or amendments, but councils are not obliged to negotiate every application. Where changes are accepted during determination, the applicant may be asked to agree an extension of time.
8. Decision
The council approves the application, usually with conditions, or refuses it with written reasons. Some applications are determined by a planning committee, but many householder and minor applications are decided under delegated powers by planning officers.
When should you speak to an architect?
You do not legally need an architect to submit a planning application. However, professional design and planning advice can be valuable where the proposal affects an older or characterful property, involves structural change, sits within a conservation area, has been refused before or needs to balance several competing constraints.
An architect can help you:
- establish the likely approval route
- understand planning risk before committing too far
- develop a design around light, layout, comfort and everyday use
- prepare accurate drawings and proportionate supporting information
- coordinate other consultants where needed
- manage the application and explain the decision
If you are still deciding whether to buy a property that needs substantial work, early architect advice before purchasing a London home can help you test design potential and planning risk before you commit.
If you need property-specific help, see GOAStudio’s planning permission services in London or request a free Feasibility Review.
How long does planning permission take in London?
Most householder and other non-major planning applications have an eight-week statutory determination period from validation. Major applications normally have a thirteen-week period. Applications can take longer where additional information or amendments are needed, the proposal goes to committee or an extension of time is agreed.
The Planning Portal explains that most planning applications are normally decided within eight weeks, with a longer period for unusually large or complex development.
The overall project programme is longer than the determination period. Time is also needed for survey work, design development, consultant input, application preparation and validation. Heritage projects and schemes requiring specialist reports generally need longer preparation.
Planning permission in conservation areas
Conservation areas are designated because of their special architectural or historic interest. The designation does not mean that every alteration requires planning permission, but some permitted development rights are more restricted and local Article 4 Directions may bring additional work under planning control.
Historic England explains that an Article 4 Direction can require planning permission for specified alterations that would otherwise fall within permitted development. Check the exact direction and property coverage rather than assuming that the same controls apply throughout a borough.
For an extension, roof alteration or window replacement, the council may consider visibility, original features, established building patterns, materials and the relevant Conservation Area Appraisal. The purpose is to preserve or enhance the area’s character, not to prevent all change.
Read more about GOAStudio’s approach to period and conservation-area homes in London.
Planning permission and listed building consent
A listed building may need both planning permission and listed building consent. Listed building consent is required for demolition, alteration or extension that affects the building’s character as a building of special architectural or historic interest. It can apply to internal as well as external work.
Historic England advises owners to establish whether listed building consent is required before work begins. Carrying out unauthorised work affecting the character of a listed building is a criminal offence.
A listed building application normally needs proportionate heritage information explaining the building’s significance, the effect of the proposal and how harm has been avoided or minimised. Early discussion can be particularly useful where original fabric or plan form would be affected.
GOAStudio’s listed building architect service contains further guidance and relevant London projects.
What happens if planning permission is refused?
A refusal notice must explain the planning reasons for the decision. The first step is to review those reasons alongside the officer report, submitted design, relevant policies and any consultation responses.
The most proportionate response may be:
- revising the design and submitting a new application
- obtaining further evidence or specialist advice
- discussing the refusal with the planning officer
- seeking pre-application advice on a materially revised proposal
- appealing where there are sound grounds to challenge the decision
An appeal is not automatically the best response. If the refusal identifies a design problem that can be resolved without undermining the project, a revised application may be quicker and more constructive.
For a householder planning application, the normal appeal deadline is twelve weeks from the date of the decision notice. Other appeal periods differ, so check the notice and current government guidance. GOV.UK explains how long you have to appeal a householder planning decision, while the Planning Portal outlines options after refusal or delay.
What happens after planning permission is granted?
Planning permission is an important milestone, but it is not normally the end of the design and approval process. Before work starts, you may still need:
- to discharge planning conditions
- Building Regulations approval and coordinated technical drawings
- structural calculations and details
- a Party Wall award or other Party Wall procedure
- freeholder or Licence to Alter consent
- build-over approval or other utility agreements
- tender information and a suitable building contract
Read the decision notice carefully. Some conditions must be discharged before work begins, while others control materials, landscaping, construction details or later stages of the project.
Do you need planning permission for your London project?
You are likely to need planning permission if the work falls outside permitted development limits, affects a flat, creates additional homes, materially changes the use of a building or is subject to a specific local restriction. However, every property and proposal should be checked individually.
Projects that commonly need a planning application
- rear, side or wraparound extensions outside permitted development limits
- two-storey extensions and substantial additions close to boundaries
- mansard roofs, raised ridges and larger roof extensions
- external alterations and extensions to flats and maisonettes
- new or enlarged roof terraces and balconies
- the subdivision of a house into flats
- the amalgamation of separate dwellings where this amounts to development in planning terms
- commercial-to-residential conversion where the proposal is not covered by permitted development
- infill, backland and other new residential development
- work affected by conservation-area controls, an Article 4 Direction or a planning condition
This is not a definitive list. The Planning Portal’s guidance on whether home improvement work needs planning permission is a useful starting point, but local restrictions and the history of the property can change the answer.
Flats and maisonettes
Flats and maisonettes generally do not benefit from the householder permitted development rights available to many single houses.
External alterations, extensions, roof works and changes affecting the number of residential units are therefore more likely to need a planning application.
Leasehold consent is separate again. Even where planning permission is not required, your lease may require the freeholder’s consent or a Licence to Alter. Building Regulations and Party Wall matters may also apply.
Small residential developments and conversions
Proposals that create additional homes—through subdivision, conversion, extension or new building—normally require a full planning application unless a specific permitted development route applies.
The council will consider the principle of development alongside the quality of the resulting accommodation, access, refuse and cycle storage, neighbouring amenity and any borough-specific housing policies.
Early feasibility is particularly important before purchasing or committing to a development site.
GOAStudio’s architects for property developments in London page explains the planning and design issues relevant to conversions, infill sites and small schemes of up to around 10 homes.
How do London councils assess planning applications?
London councils assess planning applications against policy and the particular circumstances of the site. Planning history can be relevant, but an approval elsewhere in the street does not automatically establish that an apparently similar proposal will be acceptable.
Differences in orientation, plot shape, neighbouring windows, extension depth, roof form, materials or heritage context can produce a different planning assessment.
Scale, form and relationship with the original building
Officers consider whether an extension or alteration is proportionate to the original property and how it fits with the pattern of development around it. This can involve overall height and depth, roof form, visibility and the cumulative effect of earlier additions.
Daylight, outlook and sense of enclosure
The effect on neighbouring windows, rooms and gardens is a central consideration. A proposal may be reduced or redesigned where its position and mass would cause unreasonable loss of light, outlook or an overbearing relationship.
Privacy and overlooking
New upper-floor windows, roof terraces, balconies and raised external areas can introduce overlooking. Councils consider distances, angles of view, existing screening and the relationship between habitable rooms and gardens.
Design, materials and local character
A contemporary extension is not automatically unacceptable, but its form, proportions, detailing and materials should respond to the property and its surroundings. In more sensitive settings, the council may expect a clearer explanation of how the design relates to local character.
Heritage
For conservation areas and listed buildings, the assessment considers the significance of the heritage asset and how the proposal affects it. The level of supporting information should be proportionate to the importance of the asset and the likely effect of the work.
Quality of new accommodation
Conversions and new homes are also assessed against standards for internal space, daylight, outlook, privacy, access and amenity. A scheme that creates additional units must demonstrate that the resulting accommodation will be suitable to live in.
Sustainability and environmental considerations
Depending on the project and borough, councils may consider energy strategy, overheating, drainage, biodiversity, trees, flood risk and whole-life environmental performance. These requirements are more extensive for new housing and larger developments.
Planning permission and permitted development: what is the difference?
Permitted development rights are a national planning permission granted for specified types of work. If a proposal meets every relevant limit and condition, a full planning application may not be required.
For houses, permitted development can cover certain rear extensions, roof alterations, outbuildings and other work. The detailed rules vary by project type and can be affected by previous development, planning conditions, designated land or an Article 4 Direction.
The Planning Portal explains that permitted development rights do not apply in the same way to flats, maisonettes and other buildings, and that rights are more restricted for some work in designated areas.
What is a Lawful Development Certificate?
A Lawful Development Certificate provides formal confirmation that a proposed or existing use, operation or development is lawful for planning purposes. It is not planning permission and it does not make work lawful if the proposal falls outside the development described in the certificate.
An application is not compulsory in every permitted development case, but a certificate can provide useful evidence for future conveyancing, refinancing or questions about whether work was lawful. The Planning Portal provides guidance on Lawful Development Certificates and the application route.
GOAStudio’s permitted development architectural service explains how we assess the rules and prepare Lawful Development Certificate applications for London homes.
What is planning permission?
Planning permission is the formal approval normally required for certain building works, changes to land and changes of use.
The planning system considers whether development is acceptable in its location, taking account of design, scale, neighbouring amenity, local character, heritage and relevant planning policy.
Your London borough is the Local Planning Authority for most residential applications. It assesses proposals against national planning policy, the London Plan, its own Local Plan and relevant supplementary or design guidance.
The government’s Plain English guide to the planning system provides a useful overview of how planning decisions are made in England.
Planning permission does not establish whether a project is structurally sound or technically compliant.
Those matters are generally addressed through Building Regulations and the project’s technical design.
Side extensions, larger homes and corner plots
In Wandsworth, side space is not always spare space; it can be part of the character of the street, especially where gaps between houses are important.
This is particularly relevant for detached and semi-detached houses, end-of-terrace homes and corner plots.
A side extension may create useful space, but it can also close the gap between buildings, unbalance the original façade or appear bulky.
In some streets, the rhythm between houses is as important as the houses themselves. On corner plots, a side addition may also be highly visible from the side road.
When handled well, a side extension can make the house feel more balanced and useful without eroding the rhythm of the street.
Early design advice can help test set-backs, roof form, materials, side access, boundary space and how the proposal will sit in the street.
Further authoritative planning information
Understanding how planning permission works in London can help you ask better questions, allow enough time for the process and avoid committing to a design before the main constraints are understood.
The sources below provide national and heritage guidance; your borough’s own planning pages should be checked for local policies, validation requirements and Article 4 Directions.
- GOV.UK: Plain English guide to the planning system
- Planning Portal: Do you need planning permission?
- Planning Portal: Permitted development rights
- Planning Portal: Lawful Development Certificates
- Planning Portal: Planning application decision-making process
- GOV.UK: Before submitting a planning application
- GOV.UK: Building Regulations approval
- Historic England: Conservation areas
- Historic England: Listed building consent
- GOV.UK: Appeal a householder planning decision
If you are trying to understand what may be possible for a particular property, contact GOAStudio to request a free Feasibility Review.
Frequently asked questions
Do I always need planning permission for a London house extension?
No. Some house extensions can be built under permitted development rights if every relevant limit and condition is met. Planning permission may still be required because of the extension’s size or position, conservation controls, an Article 4 Direction, a planning condition or the type of property.
Can permitted development rights be removed?
Yes. A planning condition on an earlier permission can remove particular rights, and a council can use an Article 4 Direction to require applications for specified work that would otherwise be permitted development. Check the exact legal restriction applying to the property.
Should I apply for a Lawful Development Certificate?
A certificate is not compulsory for every permitted development project, but it provides formal evidence that the proposal is lawful in planning terms. It can be useful when selling or refinancing the property or if the permitted development position is not immediately obvious.
Does planning permission mean I can start building?
Not necessarily. You may still need to discharge conditions, obtain Building Regulations approval, complete structural design, address Party Wall matters and obtain freeholder or other third-party consents.
Can neighbours stop a planning application?
Neighbours can comment on an application, but objections do not automatically cause refusal. The council considers whether comments relate to material planning matters such as privacy, daylight, outlook, design or traffic rather than private disputes or the effect on property value.
Does a previous approval next door mean my project will be approved?
No. Neighbouring approvals can be relevant, but each application is assessed on its own circumstances and against the policy in force at the time. Differences in design, orientation, plot layout and neighbour relationships can lead to a different decision.
Can I change the design after planning permission is granted?
Minor changes may sometimes be addressed through a non-material amendment, while more substantial changes may require an application to vary a condition or a new planning application. The correct route depends on the nature and extent of the change.
How long does planning permission remain valid?
Planning permissions commonly include a condition requiring development to begin within three years, but the decision notice controls the actual period. Listed building consent and other approvals may have related but separate requirements.
Can GOAStudio help after a refusal?
Yes. GOAStudio can review the refusal reasons, officer report, drawings, planning history and current policy position, then advise whether redesign, further evidence or an appeal appears to be the more proportionate route.
Not sure where to start with your renovation or extension?
Read this before you meet an architect, speak to a builder or spend money on drawings.
This free, architect-prepared guide walks you through the 15 essential questions every homeowner should ask before starting a project.
"Should we renovate, extend… or walk away?
15 Questions every London homeowner must ask before starting a project to include homes in Conservation Areas and Listed Buildings."
Whether you're planning a modest rear extension or major alterations to a listed home, it will help you avoid expensive mistakes and give you clarity on what’s possible for your property. Includes guidance on:
Planning approvals. Conservation areas.
Timelines and costs. Appointments you need to make.
Design and sustainability options.
When to press ahead and when to walk away
We provide architectural services for residential projects in the following London Boroughs:
Barnet, Camden, Enfield, Hackney, Hammersmith and Fulham, Haringey, Islington, Kensington and Chelsea, Lambeth, Lewisham, Newham, Tower Hamlets, Waltham Forest, Wandsworth, Westminster
We specialise in
- Greener homes
- Retrofit and energy efficiency for older and traditional buildings
- Conservation areas
- Listed Buildings
- Homeowner architectural services
- Property developments architectural services
GOAStudio London residential architecture limited.
86-90 Paul Street, EC2A 4NE, Hackney
Chestnut Avenue South, E17 9EJ, Waltham Forest
t: 0203 984 3005
