How to Check Planning Permission by Postcode

Why Planning Data Matters Before You Buy or Build

A house in a conservation area looks charming until you discover you cannot replace the windows without listed building consent. A brownfield plot seems like a development opportunity until the planning portal reveals it sits on a floodplain with an active Article 4 direction removing permitted development rights. Planning constraints are invisible to a casual viewer but they dictate what you can and cannot do with a property — and ignoring them can cost tens of thousands of pounds in rejected applications, enforcement notices, or reduced property value.

Planning data in England is fragmented across 300+ local planning authorities, each with its own portal, its own data format, and its own response times. Checking whether a postcode falls within a conservation area requires one lookup. Checking for Article 4 directions requires another. Checking for Tree Preservation Orders, listed buildings, Green Belt, SSSI designations, and AONB boundaries requires several more — each from a different source. By the time you have assembled the full picture, you have spent hours navigating government websites that were not designed for this kind of cross-referencing.

For property buyers, this matters at the offer stage. A property with heavy planning constraints is worth less than an identical property without them, because the constraints limit what future owners can do. For developers, this matters at the site selection stage — before spending money on architects and planning consultants, you need to know whether the site is buildable at all. For conveyancers, planning searches are a standard part of the transaction process, but the manual version takes days and costs the client money.

The Planning Intelligence endpoint combines all of these checks into a single API call, returning named constraints, planning application history with approval rates, and a proprietary Development Score that quantifies how buildable a location actually is.

How to Check Planning Data for Any Postcode

The quickest way to get a planning overview is our free Postcode Profiler tool. Enter any UK postcode and you will see a summary of planning constraints, flood risk level, and nearby designations alongside crime, demographics, and other area data. The free tool gives you enough to know whether a location has obvious planning issues before you commit to a deeper investigation.

For detailed planning intelligence, the Planning Intelligence API returns the full picture in one call. A request to /api/v1/planning/{postcode} returns named constraints (not just boolean flags — you get the actual conservation area name and Article 4 direction names), planning application data with counts by status, council performance metrics, environmental designations, flood risk, and the Development Score.

The endpoint supports three depth levels. Summary depth costs 4 credits and returns the Development Score, constraint level, and key flags. Standard depth costs 12 credits and adds application breakdowns, council performance, and designation details. Full depth costs 24 credits and includes brownfield site data, mining risk assessment, and the complete constraint inventory.

The government alternative is to search each council's planning portal individually, then cross-reference Natural England's MAGIC map for designations, the Environment Agency for flood data, and the Coal Authority for mining risk. Each source has different authentication requirements, different data formats, and different update frequencies. The API normalises all of this into a single JSON response with consistent field names, making it practical to check dozens or hundreds of postcodes without manual effort.

Understanding Planning Constraints

Planning constraints are legal designations that restrict what can be built, altered, or demolished in an area. Some are obvious — Green Belt land has strong protections against new development. Others are subtle — an Article 4 direction can remove your right to build a rear extension without planning permission, even though neighbouring streets retain that right.

The most common constraints the API returns include conservation areas, which protect the character of historic areas and require consent for demolition, certain alterations, and tree works. There are approximately 10,000 conservation areas in England. Listed buildings carry their own consent requirements (Grade I, II*, or II) and affect not just the building itself but often its setting. Green Belt designation exists around major urban areas to prevent sprawl — while not an absolute ban on development, the bar for approval is significantly higher.

Article 4 directions are particularly important because they are not widely understood. Under normal permitted development rights, homeowners can make certain changes — small extensions, loft conversions, outbuilding construction — without applying for planning permission. An Article 4 direction removes some or all of these rights for a specific area, meaning you need full planning permission for changes that would be automatic elsewhere. The API returns the names of active Article 4 directions so you can see exactly which rights have been removed.

Tree Preservation Orders protect individual trees or groups of trees. Removing or significantly pruning a protected tree without consent is a criminal offence with fines up to £20,000. The API flags whether TPOs exist in the area, which matters for anyone planning building work that might affect trees on or near the boundary.

Reading Planning Application Data

Beyond constraints, the API returns data about recent planning applications in the area — what has been applied for, what was approved, what was refused, and what is still pending. This application history is a leading indicator of development activity and council attitudes.

The response includes total applications found, approval rate as a percentage, refusal rate, pending count, and withdrawn count. An area with a 90% approval rate and high application volume is a market where the council is broadly supportive of development. An area with a 45% approval rate suggests a restrictive planning environment where applications face significant scrutiny.

Individual applications include the reference number, description, application type (full, outline, householder, prior approval), status (approved, refused, pending, withdrawn), and decision date. For developers, scanning recent applications reveals what types of development the council has approved nearby — if similar extensions or change-of-use applications have been granted, yours is more likely to succeed.

Council performance data adds another layer. The API returns the local authority's overall approval rate, the percentage of major and minor applications determined on time, and the average determination period. Councils that consistently miss their statutory determination deadlines (8 weeks for minor, 13 weeks for major) may indicate under-resourcing, which can mean longer waits and less predictable outcomes.

The response also includes a direct URL to the council's planning portal, so you can drill into specific applications without having to search for the right portal yourself. For a country with 300+ local planning authorities each with a different web interface, this saves significant time.

The Development Score Explained

The Development Score is a proprietary rating from 0 to 100 that quantifies how viable a location is for development. It synthesises multiple data points — constraint density, application history, environmental designations, council efficiency, and physical hazards — into a single number that answers the question: how easy is it to get planning permission here?

The score is calculated from seven weighted factors. Constraint density carries the highest weight at 25%, measuring the cumulative burden of conservation areas, Green Belt, listed buildings, Article 4 directions, and Tree Preservation Orders. A postcode with no constraints scores well on this factor; one inside a conservation area with listed buildings nearby and an active Article 4 direction scores poorly.

Development momentum accounts for 20%, based on the recent planning application approval ratio. High approval rates indicate a permissive planning environment. Environmental designations contribute 15%, measuring proximity to SSSIs, AONBs, and National Parks — developments near these designations face additional scrutiny. Council efficiency adds 15%, based on the local authority's approval rate and on-time determination percentage.

Brownfield opportunity accounts for 10%, reflecting nearby brownfield site availability. Brownfield land is generally favoured for development in national planning policy, so its presence can indicate opportunity. Flood risk contributes 10% via Environment Agency flood zone classification. Mining risk adds the final 5% from Coal Authority data.

The score maps to five bands: 0-24 is HIGHLY_CONSTRAINED (significant barriers to any development), 25-39 is CONSTRAINED (development possible but challenging), 40-59 is MODERATE (standard planning process with typical constraints), 60-74 is FAVOURABLE (few constraints, supportive council), and 75-100 is HIGHLY_FAVOURABLE (minimal constraints, strong development momentum, efficient council).

Practical Use for Property Decisions

For individual homebuyers, a planning check before making an offer can prevent expensive surprises. A property in a conservation area may be beautiful, but the restrictions on alterations reduce future flexibility. An area with a low Development Score may mean that the extension you were planning will face a difficult approval process. Running a planning check costs 12 credits at standard depth — roughly 2p — compared to a formal planning search through a conveyancer that typically costs £100-200 and takes days.

For property developers, the Development Score enables rapid site screening. Instead of manually checking each potential site against half a dozen data sources, a single API call returns a composite viability assessment. A developer evaluating 50 potential sites can screen all of them in seconds, filtering out locations scoring below 40 and focusing due diligence on sites scoring above 60. This reduces wasted time on sites that were never viable.

For conveyancing firms handling multiple transactions simultaneously, the API replaces the manual planning search process. A standard conveyancing search involves ordering a local authority search (which takes 2-10 working days depending on the council), a drainage search, an environmental search, and a planning search. The API returns planning and environmental data instantly, enabling firms to provide clients with preliminary results within minutes of instruction rather than weeks.

The endpoint also supports monitoring. By polling a postcode periodically, developers and investors can track new planning applications, changes in approval rates, and shifts in the Development Score over time — enabling data-driven decisions about when and where to invest.