Making a disclosure to HMRC
HMRC has three main routes for declaring tax you have not previously reported: the Let Property Campaign for individual landlords, the Worldwide Disclosure Facility for offshore income and gains, and the digital disclosure service for everything else. Penalties depend heavily on whether the disclosure was unprompted, made before HMRC approached you, or prompted by contact from them.
Almost every disclosure we handle begins the same way: someone has known about it for a while, assumed it was worse than it is, and put off finding out. The arithmetic runs the other way — the cost rises with every month of waiting and jumps the day a letter arrives.
Why HMRC is writing to people now
Because it has the data. Financial account information is exchanged automatically between tax authorities; crypto platforms report user data; letting agents, deposit schemes and online marketplaces all report. A nudge letter is generally the output of a reconciliation, not a guess.
That changes the calculation on waiting. The old assumption — that an omission from years ago is probably lost — describes a system that no longer exists.
The two questions that set the price
Unprompted or prompted
Penalties depend heavily on whether the disclosure was unprompted, made before HMRC approached you, or prompted by contact from them. The reduction available for an unprompted disclosure is substantial, and in some careless-error cases the penalty can fall to nothing.
This is the one variable still entirely within your control, and it expires without warning — the moment HMRC writes to you.
Careless or deliberate
This decides how many years are open: 6 years against 20 years. It is a judgement about behaviour rather than a fact, which means it is arguable — and it is where representation earns its fee, because the difference between the two characterisations is usually far larger than the cost of the work.
Find out where you actually stand — confidentially
Tell us roughly what and how long. We will work out which route applies, which years are genuinely in scope and what the realistic range is, before anything is submitted. Free, and nothing goes to HMRC without your instruction.
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Free assessment first. If there is work to do, you get a fixed quote in writing before anything starts.
How a disclosure runs
- Establish the position privately — years, amounts, allowable costs, and which characterisation the facts support.
- Choose the route: Let Property Campaign, Worldwide Disclosure Facility, or the digital disclosure service.
- Notify HMRC, which starts the clock — 90 days from the date HMRC acknowledges your notification under the Let Property Campaign.
- Submit the disclosure with the calculation, including the penalty position you are proposing and why.
- Pay, or agree time to pay in advance if the money is not there.
Step one before step three, always. Notifying first starts a deadline you then spend looking for bank statements.
If a letter has already arrived
Then the disclosure is prompted and that cannot be undone — but almost everything else is still open. Do not reply from memory, do not sign a certificate of tax position, and do not send documents before the scope is understood. Our guide to HMRC letters covers what each type actually means, andcompliance checks covers what happens if it has gone further than a letter.
Questions people ask
Which disclosure route applies to me?
Undeclared UK or overseas rental income as an individual: the Let Property Campaign. Offshore income, assets or gains: the Worldwide Disclosure Facility. Everything else, including undeclared self-employment and company matters: HMRC's general digital disclosure service. Choosing the wrong one wastes weeks.
What is the difference between unprompted and prompted?
Unprompted means you came forward before HMRC gave you any reason to think they were looking. Prompted means after a letter, a nudge, or an enquiry. Penalties depend heavily on whether the disclosure was unprompted, made before HMRC approached you, or prompted by contact from them. It is the single largest lever you still control.
I received a nudge letter. Am I still unprompted?
No. Once HMRC has written, a subsequent disclosure is prompted. It is still far better than doing nothing — but it is why the window to disclose on the best terms is the one before the letter arrives, not after.
Should I sign the certificate of tax position they sent?
Not without establishing your actual position first. It is not a form you are legally obliged to complete, and signing an inaccurate one moves the characterisation of your behaviour from careless towards deliberate — which is the difference between six years and twenty.
How far back does a disclosure have to go?
4 years for an innocent error, 6 years for carelessness, up to 20 years for deliberate concealment. Offshore matters have their own extended limits. Establishing which applies is usually the most valuable part of the work.
Will you report me?
We are required by law to report suspicion of money laundering, and where that applies we are prohibited from telling you. That is true of every regulated accountant in the country. What we can say plainly is that unpaid tax being put right voluntarily is ordinary work, and it is the reason disclosure routes exist.
Figures are for the tax year shown and change every April. They are general information, not advice — we check the current position for your circumstances before anything is filed.
Reviewed 19 October 2026.
Part of our work on hmrc letters and disclosures — if you want someone to take it off your hands, start with our what your HMRC letter means page.