Governance note: private rented homes check
Mithril Solutions Limited, 7 October 2026. For the council's data protection officer, before anyone acts on the list of leads.
What the check does
The check reads open data and finds homes that a council can look at. Each result is a lead to check. It is not a finding that a landlord broke a rule, and the check never says so. A council officer decides what happens next. Nothing in the check scores or ranks a home or a person.
- Rule 1 finds homes that the latest energy certificate (EPC) records as privately rented and rated F or G. The certificate must be from the last 10 years.
- Rule 2 finds privately rented homes inside a selective licensing area that match no entry on the council's licence register.
What goes where
| Output | Who gets it | What it holds | Sharing level |
|---|---|---|---|
| Public file, one for each borough | Anyone, on the homes check web page | Counts of leads in each ward, the method, the sources | 0, counts only |
| Leads list | The council's private rented housing team only | One row for each lead: address, UPRN (the national property number), certificate number and link, rating, date, the rule and its reasons, the link score | 2, identifies homes |
Both outputs come from the same records through one gate. The gate refuses a release if a field sits above the level of the person who asks. It also refuses a public file that holds text in the shape of a postcode. The gate writes each release and each refusal to an audit log. Each log line holds the hash of the line before it, so a changed line shows.
Personal data
- No data about residents. The check never collects names, dates of birth, contact details or anything about the people in a home. The public file holds counts only.
- The leads list can be personal data about landlords. An address of a privately rented home, with facts about it, can relate to a landlord who is a person. So the council treats the list as personal data. The list holds no landlord names.
- The licence register holds personal data. By law it lists licence holder and manager names and addresses. The check uses only the property address and the licence dates. No name from the register enters any output.
- The exemptions register search keeps no names. For each entry it keeps the property address, the exemption type and the date of registration. It does not keep the landlord's name.
- The council's lawful basis is for its data protection officer to decide. The leads support two duties the council already has:
- enforcement of the Energy Efficiency (Private Rented Property) (England and Wales) Regulations 2015 (regulation 34)
- its licensing schemes under the Housing Act 2004, Parts 2 and 3
Why the addresses are not published
- Licence terms. The address and postcode fields in the EPC data belong to Ordnance Survey and Royal Mail. MHCLG publishes them for a short list of permitted uses. Anyone who shares them must include the copyright notice. The leads list carries that notice in a file called READ-FIRST.
- Harm. A public list of addresses could point at landlords and at tenants' homes, and a lead is not a finding.
- Purpose. The council needs the addresses to act. The public needs only the scale of the problem.
How each rule fits the permitted uses of the EPC address data:
- Rule 1 fits "the effective management of properties in the private or public sector with a view to promoting energy efficiency".
- Rule 2 fits "the prevention or detection of crime". Letting a home without a licence that a scheme requires is an offence under the Housing Act 2004. A rule 2 lead is not evidence of an offence.
- We ask the council's data protection officer to confirm both readings.
- All other fields, including the UPRN, are under the Open Government Licence. The council can also look up each UPRN in its own AddressBase. Councils get AddressBase free under the Public Sector Geospatial Agreement.
Sources and licences
| Source | Licence |
|---|---|
| Energy Performance Certificates (MHCLG) | Open Government Licence v3.0, except the address and postcode fields (Ordnance Survey and Royal Mail notice, permitted uses only) |
| OS Open UPRN (Ordnance Survey) | Open Government Licence v3.0. Contains OS data © Crown copyright and database right 2026 |
| Ward boundaries and Postcode Directory (ONS) | Open Government Licence v3.0. Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026 |
| The council's licence register | The council's own statutory register (Housing Act 2004, section 232). Used only when the council supplies a copy |
| PRS Exemptions Register (DESNZ) | Open Government Licence v3.0 (site footer). It has no download, so a script searches its public page one postcode at a time, for the rule 1 leads only |
The full table, with access routes and restrictions, is in docs/sources.md.
How long we keep data
Kel Alaike set these periods on 8 October 2026 (DECISIONS D27). The council can ask for shorter periods.
| Data | Where | How long |
|---|---|---|
| Open data downloads (certificates, address points, boundaries, postcodes) | Mithril's laptop, encrypted disk (FileVault) | Until the next release of each source replaces them, and no more than 6 months |
| A copy of the council's licence register | Same laptop | 1 year after the leads list goes to the council, then deleted |
| The postcodes searched on the exemptions register, and the search results | Same laptop, and the civic-link/ folder of Mithril's private Google Cloud bucket (Belgium, europe-west1). Only the search job's own account can read that folder |
1 year after the leads list goes to the council, then deleted |
| The leads list | Same laptop, and the council | Mithril deletes its copy 1 year after delivery. The council keeps the list under its own retention policy |
| The audit log | Same laptop | 2 years. It holds counts, names of files and hashes, and no record content |
Raw data, the register copy and the leads list never enter a code repository and never go on a public site.
Wording
Every output, email and web page says "leads to check". None of them calls a lead a "breach", "illegal" or an "offence". Each lead shows the rule, each fact behind it, the source and date of each fact, and the link score. So an officer can see why the check found the home, and can see where the check can be wrong.
Known limits
- An EPC records tenure on the day of the assessment. A home can change from rented to owned, or the other way, after that day.
- The exemptions register has no download. A script searches it one postcode at a time, and a register entry matches a home by postcode and flat or house number. An entry with an incomplete address can miss its home. So the council still checks each rule 1 lead on the public register before it acts.
- A licence application in progress is not on the register, by law. A landlord in that position has a defence. So rule 2 leads in a new scheme include homes whose landlords have applied.
- The link between a register entry and a home has a score. A missed link makes a false lead. The method note gives the measured accuracy. AI reviewers labelled the sample of links, not a person: two on their own, and a third where they differed. The figure stays "provisional" while any sampled link has no label.
- Two addresses that name different flats, or different house numbers, are never linked. When only one of two addresses names a flat, a person must review the link.
- Before any list goes to a council, Mithril checks 20 leads in each borough by hand. The first check, on 8 October 2026, found 3 wrong leads in 40. The rule fix that followed removes all 3.
- Some homes meet rule 1 but need a person to look first: an active exemption names their building and no flat, or their certificate can belong to one of several flats. The leads list shows these homes in a separate review part. No public count includes them.
Contact
Kel Alaike, Mithril, kel@mithrilcorp.co.uk.