What Is Planning Permission: Your 2026 Guide
- Harper Latter Architects
- 2 days ago
- 11 min read
You're probably at the stage where the ideas feel exciting and slightly unruly at the same time. A rear extension that finally opens the house to the garden. A basement that gives you a proper cinema, gym or guest suite. A careful refurbishment that makes a period property work beautifully without losing its character.
Then planning permission enters the conversation, and the project suddenly feels more legal than creative.
That shift unsettles a lot of homeowners in Wimbledon, Richmond and the wider South West London area. The concern usually isn't just, “Will I get consent?” It's also, “What counts as planning permission, what can I do without it, and how do I avoid wasting months on the wrong route?” For high-value homes, especially in conservation areas or on heritage-sensitive sites, those are the right questions to ask early.
Your Home Renovation Dream and the Planning Hurdle
A good residential project starts with ambition, but it moves forward through permission, evidence and timing. If you want a glazed family extension, a major internal reworking, or a basement beneath a valuable London home, planning isn't a box-ticking exercise sitting somewhere near the end. It shapes the design from the start.
For affluent homeowners, the risk isn't usually a lack of vision. It's assuming the planning system will see the project the same way you do. A homeowner sees extra light, better circulation and long-term value. The council sees effect on neighbours, effect on the street scene, heritage impact, trees, drainage and policy compliance.
Practical rule: The more visible, complex or heritage-sensitive the proposal, the earlier planning strategy needs to sit alongside design strategy.
That's particularly true in South West London, where many of the most desirable addresses come with added scrutiny. Conservation areas, listed fabric, deep gardens, mature landscaping and tightly set neighbouring properties all increase the number of planning questions your scheme has to answer.
Planning permission isn't there to stop good architecture. It's there to control development in a way the local authority considers appropriate for the site and its context. Once you understand that, the process becomes more manageable. The goal is to present a proposal that is both architecturally strong and planning-legible.
What Exactly Is Planning Permission
At its simplest, planning permission is formal consent from your local council to carry out development. The legal basis matters here. Planning permission is a legal prerequisite triggered when a proposal meets the statutory definition of “development” under section 55 of the Town and Country Planning Act 1990. The decision is governed by the local development plan unless material considerations from the National Planning Policy Framework indicate otherwise, as outlined in this overview of planning permission in the United Kingdom.
The practical meaning for a homeowner
In plain terms, the council asks two questions.
Is this proposal development at all?
If it is, can it proceed under permitted development, or does it need a formal application?
That's why planning isn't only about new houses. It can apply to extensions, roof changes, basements, alterations to elevations, changes of use and certain external works.
A useful way to think about it is this. Planning permission is your approval under the neighbourhood rulebook. It considers the effect of your project on the site and the wider area. It isn't concerned with whether the builder installs the correct insulation or the staircase complies structurally. That falls under building regulations.
Planning permission is not the same as building regulations
Homeowners often merge the two, but they answer different questions.
Approval | What it deals with |
|---|---|
Planning permission | Use of land, appearance, scale, effect on neighbours, heritage, policy compliance |
Building regulations | Structure, fire safety, insulation, drainage, accessibility, technical construction standards |
You might need one, or both. On a substantial residential project, you'll often need both.
Planning permission asks, “Should this proposal be allowed here?” Building regulations ask, “Can it be built safely and properly?”
Types of application you're likely to encounter
For private residential work, the most common routes are:
Householder application for works to an existing home, such as an extension or major alteration.
Full planning application for a new dwelling or more substantial forms of development.
Outline permission in situations where the principle is tested first and details follow later.
Permission in Principle for certain smaller housing schemes. The route can apply to 1 to 9 dwellings, with technical details dealt with after the initial consent, and the fee is £403 per 0.1 hectare, as explained in this guide to Permission in Principle applications.
For high-end homes in Wimbledon or Richmond, the core issue usually isn't memorising planning law. It's identifying, early, which permission route matches the ambition of the project and the constraints of the site.
Permitted Development vs a Full Planning Application
Not every home improvement needs a full planning application. Some works fall within Permitted Development Rights, which are a national grant of permission for defined types of development, provided the proposal stays within strict limits.
That sounds simple until you test a real project against the rules. A modest alteration may qualify. A refined, design-led scheme on a sensitive site often won't.
The basic difference
Permitted Development is rules-based. If the proposal meets the conditions, you can usually proceed without applying for full planning permission.
A full planning application is judgement-based. The council assesses the design against local and national policy, the site context and any material planning considerations.
Here's the clearest side-by-side view.
Aspect | Permitted Development Rights | Full Planning Application |
|---|---|---|
Purpose | Nationally pre-approved categories of small-scale development | Formal application to the Local Planning Authority |
Decision basis | Compliance with fixed criteria | Assessment against local plan policies and site context |
Typical use | Smaller extensions, some roof alterations, certain outbuildings | New houses, substantial extensions, basements, sensitive alterations |
Design freedom | Limited by detailed dimensional rules | Broader design scope, but subject to planning judgement |
Best suited to | Straightforward projects on unrestricted sites | Ambitious, bespoke or heritage-sensitive projects |
Risk point | Misreading the rules and building unlawfully | Poor strategy, weak documentation or policy conflict |
Where Permitted Development catches people out
Permitted Development isn't a free-for-all. It's narrow, and local constraints can remove or reduce those rights.
One precise example is external surfacing. Planning permission is explicitly required if you lay a non-permeable driveway or hardstanding that exceeds 5 square metres. If the material is porous, no permission is needed regardless of size, according to the HomeOwners Alliance guide on driveways and planning permission.
That sort of rule matters because it shows how technical the boundary can be. A homeowner may think, “It's only a driveway.” Planning law may treat it differently because of surface water runoff.
Why high-end projects usually need the full route
In South West London, many of the projects people care most about sit outside straightforward Permitted Development.
Basement extensions often involve excavation, lightwells, landscaping changes, structural complexity and neighbour impact.
Large rear or side extensions can exceed dimensional limits or trigger design concerns.
Homes in conservation areas often have curtailed rights, so works that might be permitted elsewhere need formal consent.
Bespoke new homes always need a full planning application.
What works well is deciding early whether the scheme should be designed for a Permitted Development route or designed properly and presented through full planning. What doesn't work is producing an ambitious design first and only later trying to force it into a route it was never likely to fit.
The Planning Application Process Step by Step
A strong planning application rarely starts with drawings alone. It starts with a strategy about what the council is likely to support, what supporting information the site requires, and where the design needs to be disciplined before it ever reaches validation.
Step one to three
The opening stages are about setting the project up correctly.
Define the brief properly Separate the essentials from the aspirations. If the project must include a basement, enlarged kitchen and garden connection, that affects the planning route from day one.
Review local planning policy Borough-specific policy matters. Merton, Richmond and Wandsworth don't read applications in exactly the same way, especially on heritage, design and residential amenity.
Seek pre-application input where appropriate For sensitive or high-value schemes, pre-application advice can be useful. It won't guarantee consent, but it can expose the likely pressure points early.
For the technical side, the application pack has to be complete. For high-end residential projects, technical specifications mandate precise documentation including a location plan, elevations, and an ownership certificate. The application fee for a new house is £578, while a householder application such as an extension is £258, as set out in the Federation of Master Builders' guide to planning permission application requirements and fees.
If you want a closer look at what councils expect visually, these planning application drawings show why clarity and completeness matter so much.
Step four to six
Once the strategy is right, the formal process becomes more orderly.
Prepare the submission pack This often includes plans, elevations, site information and written statements. On heritage-sensitive projects, the written justification matters almost as much as the drawings.
Submit through the Planning Portal or directly as required The council then checks whether the application is valid. If documents are missing or inconsistent, the process can stall before assessment even begins.
A useful explainer sits below.
Public consultation and officer review Neighbours, consultees and internal council teams may comment. The planning officer then assesses the proposal against policy and site impact.
What usually makes the difference
The best applications answer objections before anyone has raised them.
A planning officer should be able to see, quickly, why the proposal belongs on the site, why it won't unreasonably affect others, and why the documents support the case rather than muddy it.
What tends to fail is the opposite approach. Incomplete packs, inconsistent drawings, weak heritage reasoning or a design that ignores neighbour relationships often create avoidable friction.
Special Rules for Conservation Areas and Listed Buildings
The most attractive parts of South West London often come with the highest level of planning sensitivity. If your home sits in a conservation area, or if the building is listed, standard assumptions about domestic alteration usually stop being reliable.
Conservation areas demand restraint and justification
In a conservation area, the council's concern isn't only your house. It's the contribution your property makes to the character and appearance of the wider area.
That changes the design approach. Materials, roof form, façade changes, boundary treatment, window proportions and visibility from the street all matter more. Projects that might be uncontroversial elsewhere can attract close scrutiny if they alter a building's public presence.
For homeowners dealing with these constraints, this guide to conservation area restrictions is a useful starting point.
Listed buildings are a separate level of control
A listed building requires a more careful process again. Planning permission may be needed, but it can also require Listed Building Consent for works affecting its character as a building of special architectural or historic interest.
That means the design case must do two things at once:
Protect significance by understanding what matters about the existing fabric and form.
Justify change by showing why the proposal is sensitive, legible and appropriate.
Good heritage design doesn't mimic badly, and it doesn't compete for attention. It understands the building first.
What usually works in practice
Applications for listed and heritage-sensitive homes are stronger when they include a coherent planning and heritage narrative, not just attractive drawings.
A persuasive submission often includes:
Measured judgement about what should remain untouched and what can change.
Material discipline so new elements complement rather than jar.
A heritage statement that explains the significance of the building and the effect of the proposal.
Clear visual evidence through existing and proposed drawings that make the changes easy to assess.
What doesn't work is treating a listed or conservation property like a blank canvas. In these settings, planning success usually comes from precision, not force.
Common Reasons for Planning Refusal and How to Avoid Them
Most refusals aren't caused by one dramatic mistake. They come from a cluster of smaller problems that signal to the planning officer that the proposal hasn't been thought through carefully enough.
The refusal patterns that appear most often
The same themes recur across domestic applications.
Overdevelopment The scheme asks too much of the plot. Too much bulk, too much footprint, or too much excavation can make the house feel overworked in its setting.
Neighbour impact Loss of light, overlooking, enclosure and noise are common objections. Councils take these seriously, especially where buildings sit close together.
Poor contextual design A technically polished scheme can still fail if it feels out of keeping with the street or the host building.
Thin or inconsistent information Missing surveys, vague drawings or contradictory documents make officers cautious.
If you've already had a setback, this overview of what to do when planning permission is refused can help clarify whether a redesign, revised application or appeal is the right response.
The 2026 issue many homeowners still miss
One of the most important recent changes is Biodiversity Net Gain.
The recently introduced Biodiversity Net Gain mandate requires most UK developments to deliver a 10% biodiversity upgrade. By 2026, incomplete ecological surveys or failing to meet this BNG target have become a leading trigger for planning refusal, a critical hurdle for new builds and extensions, according to this technical guide on planning permission and Biodiversity Net Gain.
That matters even on refined residential projects. If your proposal affects garden land, trees, soft landscaping or site ecology, BNG can no longer be treated as a peripheral issue.
How to reduce refusal risk before submission
The most reliable way to avoid refusal is to stress-test the scheme before it reaches the council.
Ask these questions early:
Does the massing respect the plot and the street?
Have neighbour relationships been properly modelled and tested?
Is the ecological position understood, not assumed?
Do the written statements reinforce the drawings rather than repeat them vaguely?
The planning system rarely rewards optimism unsupported by evidence. It does respond well to schemes that are rigorous, well-documented and visibly adjusted to the realities of the site.
Your Next Steps Towards a Successful Project
A typical South West London project starts to wobble at the same point. The brief is clear, the budget is serious, and the ambition is high, then local policy, conservation area constraints or basement questions begin to pull the scheme in different directions.
That is usually the point to slow down and set the project up properly.
For homeowners in Wimbledon, Richmond, Putney and the surrounding boroughs, the strongest early decision is rarely about style. It is about route. A house in a conservation area, a listed building, or a scheme with a new basement and major garden changes needs a planning strategy before anyone gets too attached to a layout that the council is unlikely to support. By 2026, that also means checking whether Biodiversity Net Gain will affect the application, particularly where soft landscaping, trees or garden land form part of the proposal.
A sensible order for moving ahead
Start with the national position The Planning Portal helps clarify the main application types, the limits of permitted development, and the standard documents most domestic projects require.
Then read the borough-specific policy Merton, Richmond, Wandsworth and neighbouring councils do not interpret design quality, heritage impact or basement risk in exactly the same way. Those local distinctions often decide whether a proposal feels policy-led or speculative.
Get planning-led design advice before the scheme hardens On higher-value residential work, early architectural input often prevents expensive redesign later. That is especially true for heritage refurbishments, complex rear extensions and basement projects where structure, daylight, neighbour impact and planning policy all need to align.
Planning consent is only one part of getting a project built well. The Local Government Association reported that councils in England had granted permission for 2,564,600 homes since 2009/10, while only 1,530,680 had been completed, leaving over 1 million permitted homes unbuilt and a completion rate of approximately 59.6%, as set out in its report on the housing backlog of homes with planning permission not yet built. Permission on paper does not resolve programme risk, technical coordination or construction cost pressure.
In practice, the most successful projects bring design ambition, planning judgement and technical preparation together from the outset. Harper Latter Architects is a Wimbledon Village practice working on bespoke residential planning applications, heritage projects, basements and refurbishments across South West London.
The most effective next step is to test the site, the brief and the planning route before the project takes on a form that is costly to revise.
If you're considering an extension, basement, new build or heritage renovation in South West London, Harper Latter Architects can help turn an early idea into a clear planning strategy and a buildable design.