Data sources and method
How plots are found
For each of the 318 local authorities in England and Wales we take the council area, remove every registered freehold in HM Land Registry’s INSPIRE Index Polygons, remove roads, railways and water using Ordnance Survey open data, and keep the remaining gaps of 400 m² or more after stripping narrow slivers and verges. Each plot is then scored for how realistic an adverse-possession claim on it would be.
Sources
| Data | Source and licence |
|---|---|
| Registered land | HM Land Registry INSPIRE Index Polygons, Open Government Licence. This information is subject to Crown copyright and database rights 2026 and is reproduced with the permission of HM Land Registry. The polygons (including the associated geometry, namely x, y co-ordinates) are subject to Crown copyright and database rights 2026 Ordnance Survey 100026316. Conditions of use. |
| Roads, railways, water, buildings, woodland, sites | Ordnance Survey OS OpenMap Local and OS Open Names. Contains OS data © Crown copyright and database right 2026. Open Government Licence. |
| Common land and open-access land | Natural England and Natural Resources Wales. © Crown copyright, Open Government Licence. |
| Council boundaries | Office for National Statistics. Contains public sector information licensed under the Open Government Licence v3.0. |
| Company-owned land | HM Land Registry UK companies that own property in England and Wales, used under its licence; company status from Companies House (Open Government Licence). |
| Land-use labels | © OpenStreetMap contributors, Open Database Licence (ODbL). The land-use label on each plot is derived from OpenStreetMap; on request we will provide the method used to derive it. |
| Postcode lookup | postcodes.io (Ordnance Survey and Royal Mail open data). |
Limits
The Land Registry index is approximate and doesn’t show every lease or every recent registration, so some plots will prove to be registered. Unregistered land is usually still owned. Always check with HM Land Registry and take advice.