Where UK Address Data Comes From: PAF, ONSPD, OS Open Names and AddressBase

Reference · August 2026 · 6 min read

A practical guide to the authoritative UK address datasets, what each one contains, what it costs, and which one you actually need.

"Just download the list of UK addresses" is a request that has broken many project plans. Here is what actually exists.

Royal Mail Postcode Address File (PAF)

PAF is the definitive list of UK delivery points — around 30 million of them, updated continuously as properties are built and demolished. If you need to confirm that a specific address receives post, this is the only authoritative source.

It is licensed, not free. Most teams consume it through a reseller offering a postcode-lookup API rather than licensing the raw file, which is the pragmatic choice: you get an address-picker endpoint without maintaining 30 million rows.

Use it for: address autocomplete, delivery validation, anything customer-facing where a wrong address costs money.

ONS Postcode Directory (ONSPD)

The ONSPD maps every current and terminated UK postcode to statistical geography — country, region, local authority, ward, output area — with a grid reference and latitude and longitude for each. It is published quarterly by the Office for National Statistics under the Open Government Licence, which makes it free to use with attribution.

It contains postcodes, not addresses. There are no house numbers or street names in it.

Use it for: mapping postcodes to regions and local authorities, demographic analysis, catchment and coverage work.

OS Open Names and OS Open UPRN

Ordnance Survey's open data products include OS Open Names — a gazetteer of place names, postcode district centroids and road names — and OS Open UPRN, which publishes the Unique Property Reference Number and coordinates for every addressable location in Great Britain. Both are free under the OS OpenData licence.

Use them for: place-name search, mapping, and joining datasets on UPRN.

AddressBase

Ordnance Survey's AddressBase family combines PAF with local-authority address data and the UPRN, in increasing levels of detail up to AddressBase Premium, which includes historic and provisional addresses. It is commercial, though public sector organisations in Great Britain generally have access through the Public Sector Geospatial Agreement.

Use it for: authoritative property-level work, especially where you need a stable identifier across systems.

Northern Ireland: Pointer

Great Britain's datasets do not cover Northern Ireland's address gazetteer. Pointer, maintained by Land & Property Services, is the definitive Northern Irish address database, and PAF covers NI delivery points. Check the coverage of any dataset before assuming it includes BT postcodes.

Which one do you need?

That last row matters. Reaching for licensed address data to populate a staging database is expensive, slow, and — because PAF describes real properties — brings personal-data considerations with it once you attach names. Synthetic data is the right tool for non-production environments.

What this site uses

This generator uses the public *structure* of the postcode system — areas, districts, post towns, the counties and countries they sit in — together with ONS geography, the Ofcom numbering plan and Royal Mail's published addressing rules. It does not use PAF and does not claim to: full postcodes are completed with generated inward codes, so results are structurally valid but never live delivery points. That is documented in DATA_SOURCES.md in the repository.

If you need to verify that a real address exists, use a licensed PAF provider. If you need believable UK addresses that are safe to put in a test database, use the address generator.