Why it matters
What Let Property Campaign means for a landlord
HMRC receives data from many sources, so undeclared rent is increasingly visible. Coming forward through the Let Property Campaign before HMRC contacts you usually costs less than waiting: penalties for an unprompted disclosure are lower than for one HMRC prompts, and a deliberate failure can mean a penalty of up to 100% of the tax, on top of the tax and interest, and a longer look-back period.
Worked example
How it plays out
Colin has let a flat in Kent since 2019 without telling HMRC. In 2026 he notifies HMRC that he wants to disclose through the Let Property Campaign, receives a reference, and has 90 days to work out the tax, interest and penalty for each year and pay. Because he came forward before HMRC contacted him, his penalty is lower than it would have been if HMRC had found the income first.
Common mistakes
Where landlords go wrong
- 01Waiting for HMRC to write first, which usually means higher penalties.
- 02Leaving out years because the records are incomplete.
- 03Forgetting that interest is due on late tax.
What to do
A short checklist
- Gather rent and expense records for every year the property was let.
- Tell HMRC you intend to disclose.
- Diary the 90-day deadline.
- Register for Self Assessment for future years.
Sources
Checked against these sources on 16 September 2026. A guide to the rules in England, not legal advice: for a dispute or a possession claim, speak to a solicitor.
