For developers · Free constraint check
Enter a site postcode and we query the national planning dataset live: conservation area, Article 4 direction, listed buildings, flood risk zone and green belt. Every layer is reported, including the ones that come back clear, so you know what sits over the land before you bid.
Check a site
Live against planning.data.gov.uk. You get the designations recorded at the postcode, drawn on a map and listed in full, plus an indicative view of how complex the planning route is likely to be.
Where is the site?
We query the postcode centroid against the national planning dataset published by the Ministry of Housing, Communities and Local Government. England only.
UK postcodes only.
Querying the record
Five national datasets, for SW15 1NL.
We could not resolve that postcode
Nothing was returned for . That is usually a typo in the second half of the postcode, a new-build postcode not yet published, or a postcode outside England.
What kind of site is it?
The starting condition drives the planning route more than anything else at this stage.
Approximate site area
A band is enough. The 0.2 hectare line matters: since 6 August 2026 non-major sites of 0.2 hectares or under are exempt from Biodiversity Net Gain.
Intended use
What you would take forward if the site stacks up.
Development appraisal
A designation on a piece of land is not an abstraction. It is a line item. A conservation area moves the application from a routine validation to one where a conservation officer comments, materials are scrutinised and the design has to answer to the character of what is already there. That is additional design time, additional consultation, and a determination period that runs long rather than short. None of that stops a scheme. All of it changes the cash flow you underwrote at bid.
An Article 4 direction is sharper. It withdraws permitted development rights that would otherwise have applied, and the two that matter most commercially are the office to residential right and the house to small house in multiple occupation right. If your model assumed a prior approval route, an Article 4 direction takes it away and replaces it with a full application. Weeks become months, and a scheme that priced on certainty now prices on planning judgement.
Flood risk sits differently again. Flood Zone 2 usually means a flood risk assessment and a sequential test argument. Flood Zone 3 means the sequential and exception tests, finished floor levels driven by modelled water levels, and in some cases a residential use the council will simply resist. Listed status, whether the building is on the site or immediately adjoining it, brings setting into the assessment and adds heritage input to the team. Green belt is the hardest of the set, because it starts from a presumption against inappropriate development that has to be overcome rather than argued around.
Before the bid
Most sites that go wrong went wrong at the offer, not at determination. The bid was struck against an assumed planning route, and the constraint that killed it was discoverable on day one. Backland and infill sites are the most exposed, because the value case usually depends on a specific access arrangement and a specific relationship to the neighbouring plots, and both are the first things a constraint interacts with.
A constraints check like the one above is the ten minute version. It tells you which designations are recorded and which came back clear, and it is deliberately honest about the difference between clear and absent. The national dataset carries what councils and national bodies have published to it, and coverage is uneven between authorities. A clear result narrows your risk. It does not remove it.
What it cannot tell you is capacity. Two sites with an identical constraint profile can behave completely differently once you test them against the local plan policies, the daylight and sunlight relationships with the neighbours, the access geometry and the officer's recent decisions on comparable schemes in the same ward. That is the work that turns a constraint list into a number you can bid against, and it is not something any automated tool can do honestly.
Doing that work before the offer costs a fraction of what it costs to discover it afterwards. It also gives you something to negotiate with. A vendor asking a price built on an optimistic planning assumption is a great deal easier to move when you can show the constraint, the policy and the programme it implies.
This is the point of a development appraisal rather than a desktop skim. A residual land value only means anything once the capacity, the planning risk and the programme underneath it are real, and every one of those is moved by the designations sitting over the land. Backland development and infill development are the clearest cases, because the constraint usually lands directly on the part of the site the value depends on. An office to residential conversion is the sharpest of all, since the whole route can turn on whether an Article 4 direction has been made in that specific area.
The site appraisal
The appraisal is a written document, delivered within 10 working days of instruction, and it answers the four questions a constraint check deliberately leaves open. Achievable unit capacity and mix, tested against the site rather than assumed from a density. Developable footprint and indicative massing, drawn, with the setbacks and separation distances the constraints and the neighbours actually impose. A planning risk rating with our read on the likely officer position, based on the policies in force and the decisions that authority has been making on comparable schemes. And an indicative programme to determination, including the pre-application route where it is worth taking and where it is not.
We work the same way whether the site is a single backland parcel behind a terrace, an infill gap on an established street, or a standing building where the value case rests on a conversion. The method does not change. What changes is which constraint is doing the damage and what it takes to answer it, and that is only visible once someone has read the local plan policies against the actual land rather than against a category.
Where a constraint is present, we set out the mitigation rather than just flagging the problem. That means the heritage statement scope for a site adjoining a listed building, the flood risk assessment and finished floor level strategy in Flood Zone 2 or 3, the biodiversity position above the 0.2 hectare threshold, and the design response that gives a conservation officer something to support rather than resist.
If you appoint us for the planning application, the appraisal fee is credited against our fees. In practice that makes the appraisal free on any site you take forward, and cheap insurance on any site you walk away from. We work across Greater London and the South East, and our architectural designers, interior designers and structural engineers run as one team, so the scheme that comes out of the appraisal is the scheme that gets drawn.
If you already know the site works and you want to move straight to design, talk to us directly. If you want to sanity check a homeowner scale project instead, the planning permission checker and the cost calculator cover that ground.
Common questions
It is a first pass over the designations recorded against a piece of land: conservation area, Article 4 direction, listed buildings, flood risk zone and green belt. Each one changes what can be applied for, how the application is validated, and how long determination takes. The check tells you which designations are recorded at the postcode so you know what you are dealing with before you spend money on the site.
No. The national dataset covers designations that councils and national bodies have published to it, and coverage is uneven. A clear result means nothing was returned for that postcode, not that nothing exists. Local plan allocations, tree preservation orders, restrictive covenants, rights of light, ransom strips and drainage capacity all sit outside this dataset entirely and any one of them can stop a scheme. Verify the exact red line before you commit.
An Article 4 direction withdraws permitted development rights that would otherwise apply, so work that would have gone through prior approval has to be applied for in full. For developers the most common ones remove the office to residential and the house to small house in multiple occupation rights. If your acquisition model assumed a prior approval route, an Article 4 direction removes it, and the programme moves from weeks to months.
Since 6 August 2026, non-major development on sites of 0.2 hectares or under is exempt from Biodiversity Net Gain. Above that threshold the 10 percent gain requirement and the habitat management obligations apply, which adds survey cost, design constraint and programme before you can validate an application. This is why the site area band matters more than it looks: the same scheme either side of 0.2 hectares carries a different cost base.
Achievable unit capacity and mix, developable footprint and indicative massing, a planning risk rating with our read on the likely officer position, constraint mitigation, and an indicative programme to determination. It is delivered within 10 working days. If you appoint us for the planning application, the fee is credited against our fees.
From planning.data.gov.uk, the national planning data platform published by the Ministry of Housing, Communities and Local Government, under the Open Government Licence. The tool queries it live by coordinate, so you are seeing what is published today rather than a cached copy. Flood risk zones originate with the Environment Agency and listed building records with Historic England.