Organise the rent and costs by tax year, then identify which years need a return, amendment or disclosure. The Let Property Campaign can apply to eligible undeclared residential rental income. Follow the official acknowledgment-based timetable and get suitable help where several years are involved.
What to do first
- Stop guessing. Read HMRC’s current Let Property Campaign guide on GOV.UK and check whether that route applies to you.
- Gather what records you still have: rent received, agent statements, bank entries, repair invoices, and finance-cost paperwork.
- Separate older undeclared years from current or very recent years that may still belong on a normal Self Assessment return or amendment rather than inside a disclosure pack.
- If the calculations span several years or the paperwork is incomplete, consider professional help before you send figures to HMRC.
What the Let Property Campaign is
HMRC describes the Let Property Campaign as a way for landlords who owe tax from letting residential property in the UK or abroad to get their tax affairs up to date. GOV.UK says individual landlords can use it for situations such as a single let, a portfolio, a room in a main home above the Rent a Room threshold, holiday lettings, inherited property that is let, and some non-resident landlords of UK property.
It does not cover landlords disclosing only non-residential property such as a shop or garage, or disclosures on behalf of a company or trust. Those situations need a different route.
Notification, disclosure and payment (high level)
GOV.UK’s process has clear stages:
- Notify HMRC that you intend to make a disclosure as soon as you become aware you owe tax on letting income. At this stage you do not need to supply the full income figures.
- HMRC then gives you a disclosure reference number and a payment reference number.
- Disclose the undeclared letting income within 90 days of the date on your notification acknowledgement, and pay what you owe (or agree payment arrangements with HMRC by that same deadline if you cannot pay in full).
GOV.UK warns that if disclosure and payment (or agreed arrangements) are not completed by that deadline, you will not be able to make a disclosure under the campaign’s terms. Always use the dates on your own acknowledgement letter.
Current or prior-year income may sit on a tax return instead
HMRC’s campaign guide draws an important line: income in the current tax year should not go in the disclosure. If you are not already in Self Assessment, register now and report that income on the return HMRC issues after the year ends. Income for the year before the current tax year is also generally handled through a tax return or, if you already filed, through an amendment within the usual amendment window. Put simply, not every missed rent figure belongs in the multi-year disclosure form.
Records and incomplete paperwork
Start with bank statements, tenancy agreements, agent reports and invoices. If records are incomplete, GOV.UK says you should make your best estimate, keep your workings, and be ready to explain them. Ask your bank for copy statements early if they are missing. This is also the moment to start keeping proper property records going forward.
Tax, interest and penalties (carefully)
Any extra tax included in a disclosure is late, so GOV.UK says interest runs from the date the tax was due until it is paid. Penalties can also apply where returns were wrong or HMRC was not told about a tax liability. HMRC asks you to consider whether errors happened despite taking reasonable care, through carelessness, or deliberately. Those categories affect how many years may need to be covered and how penalties are approached. This article will not label your situation or promise any penalty outcome.
GOV.UK notes that voluntary disclosure is usually treated more favourably than waiting until HMRC finds the income another way, and that waiting can lead to higher penalties and more serious enforcement outcomes. That is HMRC’s published warning, not a prediction about you.
Why multiple years get complicated
Each year can have different rent, expenses, finance-cost rules, rate bands and other income. Losses in one year may only set against later rental profits. Joint ownership means each person usually needs their own figures and, where relevant, their own disclosure. Mixing years that belong on ordinary returns with years that belong in a disclosure makes the pack easy to get wrong.
After you bring older years up to date
Once past liabilities are addressed, future rental profit still needs correct reporting. That usually means staying in Self Assessment while it applies, keeping records, and watching Making Tax Digital for Income Tax if your property income brings you into scope. Practical prep for a normal year is in Self Assessment for landlords 2025/26; MTD timing is in MTD for landlords 2026/27.
TaxSimba provides accountant-led help with ongoing rental Self Assessment and related landlord tax compliance through our rental income tax service. We do not claim to run a specialist Let Property Campaign disclosure product on this page. If you need help getting future returns right after you have dealt with HMRC’s disclosure process, get accountant help with your rental tax. Recheck the live GOV.UK campaign guide before you act, because process details can change.
Map the years before choosing a disclosure route
Illustrative preparation example.
Prepare one line per rental year with gross rent, costs, ownership and any return already submitted. Mark where figures are incomplete. Give the adviser the full timeline so current returns, amendments and a possible disclosure are not accidentally mixed together.
Check: Which years were omitted, which were filed and which still need evidence?
| Check | Practical action |
|---|---|
| Which years and properties are affected? | Create separate annual schedules with ownership and residence details. |
| Ordinary return, amendment or disclosure? | Check the appropriate route for each year before combining figures in a campaign submission. |
| What deadline did HMRC give? | Work from the actual acknowledgement and arrange disclosure and payment or agreed terms in time. |
Should I estimate missing records without explaining them?
No. Seek replacement evidence first, retain a reasonable reconstruction and clearly explain estimates and their basis where the official process allows them.
Does voluntary disclosure guarantee no penalty?
No. The outcome depends on the facts and applicable rules. Accurate records and timely engagement support the process without guaranteeing a result.
Download a checklist for this guide
- List affected years, properties and ownership shares.
- Obtain bank and letting-agent records.
- Reconstruct income and costs year by year.
- Check the correct reporting route for each year.
- Record acknowledgement dates, deadlines and payment discussions.