# Undeclared rental income? How the HMRC Let Property Campaign works > A practical guide for individual landlords who need to disclose previously undeclared residential rental income to HMRC. Canonical: https://yestax.co.uk/tax-help/undeclared-rental-income-let-property-campaign Last updated: 2026-09-03 Published: 2026-09-03 Author: YesTax Editorial Team If you have rental income that should have been reported to HMRC but was not, **do not wait for HMRC to discover it before working out the position**. The Let Property Campaign gives many individual residential landlords a route to disclose unpaid tax and bring earlier years up to date. It is a disclosure process, not an exemption from the tax or an automatic waiver of penalties. ## Who the campaign is aimed at HMRC says the Let Property Campaign is for **individual landlords** who owe tax because of letting residential property in the UK or abroad. Common situations include: - a former home was rented out after moving elsewhere; - a buy-to-let property was never included on a tax return; - only some of the rental income was reported; - a jointly owned property was reported incorrectly; - overseas residential rental income was omitted; - expenses or taxable profit were calculated incorrectly in previous years. Not every property-tax problem belongs in this campaign. The legal ownership, type of property, taxpayer and reason for the error can change the appropriate disclosure route. ## What happens after you notify HMRC The process normally has two distinct stages: 1. **Notify HMRC** that you intend to disclose. 2. **Prepare the disclosure**, calculate the tax, interest and penalties, make an offer and pay what is due within the timetable HMRC gives you. HMRC's current guidance says that after telling HMRC about unpaid rental tax, you will then have **90 days** to work out and pay what you owe. That means it is sensible to start gathering records before notifying if the history is complicated. Ninety days can disappear remarkably quickly once humans introduce old bank accounts, missing invoices and jointly owned property into the story. ## How many years need correcting? This is one of the most important parts of the disclosure. The period can depend on the behaviour that caused the underpayment. HMRC's Let Property Campaign guidance distinguishes between situations such as: - taking reasonable care but still getting the tax wrong; - careless errors; - failing to notify HMRC that tax was due; - deliberate behaviour. HMRC's current guide notes that a person who failed to notify HMRC may in some circumstances need to account for tax going back as far as **20 years**. By contrast, shorter assessment periods can apply where the taxpayer took reasonable care. Do not simply choose the number of years that produces the nicest answer. ## Work from rental profit, not rent received The tax calculation is not normally just a percentage of gross rent. For each tax year you may need to reconstruct: - gross rent and other property receipts; - periods when the property was let or empty; - allowable property expenses; - financing costs and the rules applying in that year; - ownership percentages; - losses brought forward; - other taxable income that affects rates and allowances. The tax treatment of finance costs for individual residential landlords changed over time, so using today's treatment for older years can distort the calculation. ## Penalties depend on the facts A disclosure usually needs an explanation of why the income was not correctly reported. The difference between a reasonable mistake, carelessness and deliberate non-compliance can materially affect penalties and the years HMRC can assess. A useful disclosure therefore explains the chronology rather than merely sending a spreadsheet with one final number. ## What if HMRC has already contacted you? Voluntary-disclosure treatment can be different once HMRC has already started asking about the property or income. If you have received a compliance-check letter, nudge letter, information request or other HMRC contact about the same rental income, include that in the problem description immediately. Do not present the matter as an untouched voluntary disclosure if HMRC is already investigating it. ## What to gather before asking for help Start with: 1. property addresses and ownership percentages; 2. dates each property was acquired, first let and sold if relevant; 3. annual letting-agent statements or rent schedules; 4. bank statements showing rental receipts; 5. mortgage interest statements and finance information; 6. repairs, insurance, agent fees and other expense records; 7. tax returns already submitted for the affected years; 8. any correspondence already received from HMRC. If the records are incomplete, say what is missing. A defensible reconstruction is much better than false precision. ## The practical objective A strong disclosure should answer four questions clearly: **what income was omitted, for which years, why it happened, and what tax plus interest and penalties should now be paid?** Getting those points right matters more than producing a decorative folder labelled “HMRC” and hoping bureaucracy is impressed by stationery. ## Common questions ### What is the Let Property Campaign? It is HMRC's disclosure route for individual landlords who need to bring previously undeclared tax on residential letting income up to date. ### Can the Let Property Campaign cover overseas rental property? HMRC says the campaign can apply to residential property let in the UK or abroad by an individual landlord. ### How far back can HMRC ask me to disclose? The number of years can depend on why the tax was underpaid. HMRC's guidance describes shorter periods where reasonable care was taken and potentially much longer periods, including up to 20 years in some failure-to-notify cases. ## Primary sources - [HMRC: Let Property Campaign — guide to making a disclosure](https://www.gov.uk/government/publications/let-property-campaign-your-guide-to-making-a-disclosure/let-property-campaign-your-guide-to-making-a-disclosure) - [HMRC: Let Property Campaign enquiries](https://www.gov.uk/find-hmrc-contacts/let-property-campaign) --- This page is general information, not individual tax, legal or financial advice.