HMRC learns who is letting property from records it collects automatically: the Land Registry (who owns what), tenancy deposit schemes (which properties are let and to whom), letting agents (who must report the rent they collect), banks, local councils, mortgage lenders and online letting platforms. Its Connect system joins those records to your tax return. If you own a second property and have not declared rent, that gap is visible to HMRC without anyone reporting you.
Where the information comes from
- Land Registry. Every property purchase is recorded with the buyer’s name. If you own two homes and one address is not where you live, HMRC can see that.
- Tenancy deposit schemes. A protected deposit means a tenancy exists at that address, with the landlord named.
- Letting agents. Agents can be required to tell HMRC which landlords they collect rent for and how much.
- Banks and building societies. Interest paid on accounts, and regular incoming payments that look like rent.
- Councils. Council tax records show who is liable at an address, and selective licensing schemes register landlords.
- Mortgage lenders. A buy-to-let mortgage is a buy-to-let mortgage.
- Online platforms. Under rules that began in January 2024, platforms such as Airbnb report hosts’ income to HMRC each January — the first reports, covering 2024, were sent in January 2025.
What HMRC does with it
The Connect system links these records to Self Assessment returns and flags anyone who appears to receive rent but declares none, or declares less than the data suggests. The usual result is not a full enquiry but a nudge letter: a standard letter saying HMRC has information that suggests you may have rental income, inviting you to check your position. Many landlords receive one every year now.
The Let Property Campaign exists for exactly this situation: it lets you come forward, declare what you missed and settle on better terms than if HMRC opens an enquiry first.
What to do if you have not declared
- Do not ignore a letter. The terms get worse once HMRC starts asking questions.
- Work out what should have been declared, year by year. Our free tools help you gather the figures.
- Decide the route: usually the Let Property Campaign. Our route finder shows which applies to you.
- Tell HMRC before it asks. Voluntary disclosure means lower penalties and, often, fewer years.
Common questions
Can HMRC see my bank account?
HMRC can request information from banks and building societies and receives interest data automatically. It does not watch your account in real time, but it can obtain statements when it has a reason to.
I only let one property. Would HMRC really notice?
Yes. Most nudge letters go to landlords with a single property, because that is where undeclared rent most often sits. The data matching is automatic, not targeted at large portfolios.
How many years can HMRC go back?
Normally four years; six if the error was careless; up to twenty if it was deliberate. See our guide to penalties and time limits.
Is it better to wait and see if HMRC writes?
No. A voluntary disclosure carries lower penalties than one prompted by a letter, and much lower than one made after an enquiry has started.
This page is general information for UK landlords, not advice on your own position. Figures and rules are correct at the review date above and are re-checked after each Budget.