Where the data comes from

Every report names its sources beside each finding, with the date it was read. This page lists them in one place, with the licence, so you can read the same records yourself.

Postcodes

postcodes.io, an open service built on Office for National Statistics and Ordnance Survey open data. Gives the coordinates, the council, the ward and the country for a postcode. Open Government Licence v3.0. https://postcodes.io

Planning

planning.data.gov.uk, the national planning data platform run by the Ministry of Housing, Communities and Local Government. Article 4 direction areas, from which the report picks out the directions on HMO conversion by their record text. The platform says itself that it is not yet complete for all of England, which is why a report says not checked when a council has published nothing. Open Government Licence v3.0. https://www.planning.data.gov.uk/dataset/

Landlord licensing

The national mandatory HMO rule is read from the Licensing of Houses in Multiple Occupation (Prescribed Description) (England) Order 2018 and the Housing Act 2004 on legislation.gov.uk, with the plain guidance at gov.uk. Additional and selective licensing schemes come from a table we keep, one row per council, each read from the council's own published page on the date printed beside it. The table holds every London borough and the largest English councils. A council outside the table is reported as not checked. Ward names come from postcodes.io. The council is the final authority on whether a licence is needed.

Law

Statutes are cited from legislation.gov.uk: the Housing Act 2004, the Prescribed Description Order 2018 and the Housing and Planning Act 2016 as amended. The penalty and rent repayment figures in a report are the figures those sections give on the date the report was produced.

Attribution

Contains public sector information licensed under the Open Government Licence v3.0. Contains OS data copyright Crown copyright and database right 2026.