Using planning.data.gov.uk to check site constraints

The planning data service at planning.data.gov.uk is the fastest way to see which national and local designations touch a site, and the worst way to prove any of them. It publishes datasets supplied by local planning authorities and national bodies in one consistent structure, so you can check a conservation area boundary, an article 4 direction or a green belt edge in about a minute. What it cannot do is override the authority's adopted policies map, and on several datasets the coverage is patchy because not every authority has published yet.

Use it first, then confirm. That order saves hours on a feasibility study and keeps a constraints plan defensible.

What the service holds and who supplies it

The platform is run by the Ministry of Housing, Communities and Local Government and brings together planning and land datasets in a common format. Some are national: listed buildings drawn from the National Heritage List for England, scheduled monuments, national parks, national landscapes, sites of special scientific interest, green belt. Others are local and depend on the authority publishing them, which is where article 4 directions, conservation areas, tree preservation zones, local plan boundaries and brownfield land registers sit.

Every record carries a source organisation and a set of dates. That matters more than it sounds. A conservation area entity published by a district council with an entry date of last year tells you both what the boundary is and when the authority last touched the data. When you cite a constraint in a planning statement, cite the dataset and the date you checked it.

The structure is worth learning once. Each dataset is a collection of entities, each entity has a reference, a name, a geometry and a set of fields, and every entity has its own page and a stable link. Those links are what you paste into a report so a case officer can open the same record you looked at.

Searching by address or by dataset

There are two ways in, and architects tend to use the wrong one. Searching by location gives you a map view and the entities that intersect the point you clicked, which is right for a first look at a site. Searching by dataset gives you every entity in that dataset, filtered by organisation, which is right when you want all the article 4 directions a particular authority has made, or every conservation area in a borough.

For a site appraisal, work in this order:

1. Find the site on the map and note every entity returned at that point.
2. Open each entity page and record the reference, the name and the entry date.
3. Switch to dataset view for the authority and check whether anything sits just outside the boundary that could still matter, such as a listed building 40 metres away or a conservation area across the road.
4. Download the geometry you need as GeoJSON or CSV for the constraints drawing.
5. Cross-check the two or three constraints that drive the scheme against their primary source.

Step three is the one people skip. Setting affects heritage assets beyond their boundary, and a tree preservation order on a neighbour's land still constrains what you can build near the shared fence.

Conservation areas and article 4 directions

These two datasets carry the most practical weight for householder and small residential work, and they are the two with the most variable coverage.

A conservation area designation removes some permitted development rights and brings in the duty in section 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990 to pay special attention to preserving or enhancing character and appearance. The dataset gives you the boundary and usually a designation date. It does not give you the appraisal document, and the appraisal is where the reasons for designation and the character areas live. Go to the council's website for that.

Article 4 directions are harder. A direction withdraws specified permitted development rights in a defined area, and the detail sits in the direction itself: which classes are withdrawn, over what area, from what date. The dataset entity will often link to or name the direction, but the operative wording is the council's document. Two common examples are householder directions in historic suburbs, which remove rights to alter front elevations or remove chimneys, and directions removing the right to change from class C3 to class C4 in university towns. Reading the direction rather than the map entry is the difference between a valid prior approval and a wasted application.

If a direction does not appear on the service, that is not evidence it does not exist.

Where the data runs out

Coverage is uneven by design, because local datasets depend on authorities publishing them and on the data being in a shape the platform can take. Expect gaps in tree preservation orders, local listings, local green space, and anything the authority holds only as a scanned map in a 2006 local plan.

Three habits deal with this honestly:

• Record the absence. "No article 4 direction returned by the planning data service on 14 May, authority has not published this dataset" is a defensible line in a report. "No article 4 direction" on its own is not.
• Ask the authority directly where a gap would change the advice. Most planning services answer a short written enquiry about designations, and some charge for a formal search.
• Treat other datasets as the primary check where one exists. Flood zones come from the flood map for planning, protected sites and priority habitats from MAGIC, listed buildings from the National Heritage List for England. If the constraint drives a specialist report such as a Flood Risk Assessment, use the regulator's own map as the citation.

There is a wider point about habitat and environmental layers, which have their own classification conventions and are easy to misread from a generic map view. Our note on reading habitat inventories and classification data goes through that in more detail, and rights of way have their own legal register, covered in checking the definitive map.

Turning the data into a constraints plan

Download rather than screenshot. GeoJSON drops straight into most CAD and GIS packages, keeps the geometry accurate and carries the attributes with it, which means your constraints drawing can be regenerated when the scheme boundary moves. A screenshot cannot be re-projected and cannot be checked.

For the drawing itself, keep each constraint on its own layer, label it with the dataset name and the entity reference, and put the download date in the title block. When a case officer or a consultee questions a boundary, you can show exactly what you used.

A short worked sequence for a typical infill site, illustrative only: the map returns a conservation area and a green belt boundary at the site. The heritage layer shows two grade II listed buildings within 80 metres, which puts setting in play and points towards a Heritage Statement. No article 4 direction is returned, but the authority has not published that dataset, so a written enquiry goes off the same day. The flood map for planning shows zone 1, which is recorded with its own screenshot and date. Total time, under an hour, and every line on the constraints plan has a source.

Checking against the adopted policies map

The service is a convenience layer over the legal position, not a replacement for it. The development plan for the area is what section 38(6) of the Planning and Compulsory Purchase Act 2004 requires decisions to be made in accordance with, and the adopted policies map is the document that shows where each policy applies. Site allocations, settlement boundaries, local designations and policy-specific areas live there, and many of them never reach the national platform.

So the final check on any appraisal is the policies map and the policy text, read together. Where the two sources disagree, the adopted plan wins and the difference is worth reporting to the authority, because it usually means the published dataset is stale.

Two minutes of citation discipline protects the rest of the work. Dataset name, entity reference, source organisation, date checked. Do that on every constraint and the evidence base holds up when someone challenges it 18 months later at appeal.

This is general guidance rather than 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. Enter your postcode on PlanScope to see the constraints it detects and which reports they point to.