Getting site constraint data from planning.data.gov.uk

The national planning data platform at planning.data.gov.uk is the fastest way to assemble a constraints picture for an English site, provided you understand what it is. It aggregates datasets published by local planning authorities and national bodies into a single set of records with consistent field names, a map interface and an API. It is not a legal register, and for some datasets it is not complete.

Used properly it saves a day of clicking around council websites. Used carelessly it produces a constraints plan that misses an Article 4 direction because the council has not published one yet.

What the platform holds and who publishes to it

Records fall into two broad groups. National datasets come from bodies with a statutory register: listed buildings, scheduled monuments, registered parks and gardens and battlefields from Historic England. Natural England publishes sites of special scientific interest, special areas of conservation, special protection areas and national landscapes. The Environment Agency publishes flood risk zones.

Local datasets come from the 300 or so local planning authorities in England, and cover conservation areas, Article 4 directions, tree preservation orders, brownfield land registers, local plan boundaries and development policies. Provisions in the Levelling-up and Regeneration Act 2023 give government powers to set data standards for planning authorities, and the platform is the place that data lands.

The practical consequence: assume the national layers are authoritative and the local layers are indicative until you have checked them.

Searching by location and by dataset

Two useful entry points. The map view lets you pan to a site and switch layers on, which is the quickest way to see what intersects a boundary. The dataset view lists every record in a dataset with filters, which is the quickest way to answer questions like how many conservation areas a given authority has published.

For a site appraisal the sequence that works:

1. Find the site on the map and turn on the heritage, ecology, flood and tree layers together, so you see interactions rather than single constraints.
2. Click each intersecting entity and open its record, rather than trusting the map symbol.
3. Note the organisation that published it and the entry date.
4. Check the 500 metre surroundings, because listed buildings and ancient woodland affect a site from outside its boundary.
5. Export what you find, so the constraints plan has a dated source rather than a screenshot.

That output feeds straight into the process described in building a constraints plan before the design starts.

Reading an entity record

Every record is an entity with a number, a dataset, a name, a reference, a geometry and a set of dates. Three fields matter more than the rest.

The organisation entity tells you who published the record, which is how you know whether to verify it with the council or with a national body. The entry date is when the record entered the platform, not when the designation was made. The start date, where present, is the date the designation took effect, and the end date marks a record that has been superseded or revoked.

An Article 4 direction record with an entry date of last year and no start date tells you very little about when the direction came into force. Open the council's own document before relying on it.

Which datasets are complete and which are filling

The gaps are not errors. They reflect which authorities have published which datasets. For heritage work the National Heritage List remains the definitive source for a listing entry and its description, which is what a Heritage Statement has to engage with.

Downloading extracts and using the API

Every dataset can be downloaded in bulk, and individual searches can be exported. For a single site, the more useful route is the JSON API, which accepts a dataset name and a point or geometry and returns intersecting entities.

A short script that takes a site centroid, queries each dataset of interest and writes the results to a table will do in seconds what takes twenty minutes by hand, and it produces a repeatable record. Keep the query and the response date with the project file. When a council officer asks where a constraint came from, that file is the answer.

Two cautions. Geometry precision varies between publishers, so a boundary that appears to clip the site by a metre needs checking against the source. And the API returns what has been published, so a null result means no published record rather than no constraint.

An illustrative example

Illustrative only: a 0.3 hectare infill plot in a market town. The platform shows no conservation area intersecting the site, one grade II listed building 40 metres to the north, a flood zone 1 classification, and no tree preservation order.

The architect checks the National Heritage List entry for the listed building and finds the list description mentions attached railings, extending the curtilage question. The council's own map shows a conservation area boundary running along the far side of the road, unpublished on the platform at the time of the search. Neither point changes the scheme, but both change the documents it needs, and both were found in ten minutes.

Verifying a finding against the council's record

Three rules keep you out of trouble.

Where the platform shows a constraint, treat it as present and verify the extent. Where it shows nothing for a locally published dataset, treat that as unknown rather than absent, and check the council's website or ask in writing. Where the two disagree, the council's own adopted document wins, because that is what the decision will be taken against.

For trees and woodland the same logic applies with an added wrinkle: ancient woodland inventories and veteran tree records are national but not exhaustive, a point taken further in checking ancient woodland and veteran trees before layout. For flood zones, the platform mirrors the Environment Agency data but the Flood Risk Assessment has to be built on the live service and the council's strategic assessment.

Build the search into your standard site appraisal and record the date every time. Enter a postcode on PlanScope and the same constraint layers are checked automatically against the site you confirm.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.