A disclosure letter is a written statement used to reveal information that matters legally or financially. In the HMRC context, it usually means a disclosure made to HMRC when tax has been underpaid, income or gains have not been reported, or a taxpayer needs to correct earlier errors.
In simple terms, it is part of the process of telling HMRC what went wrong, how much tax is due, and what you are doing to put it right. HMRC’s guidance makes clear that it is better to come forward voluntarily than wait for HMRC to find the issue, because penalties are often lower where the disclosure is made by the taxpayer first.
Outside the tax context, a disclosure letter is commonly used in private legal transactions, particularly in business sales and corporate acquisitions, where a seller formally discloses information against warranties in a contract. This use is separate from HMRC disclosures and is governed by general contract law rather than tax rules.
In this article, the focus is the HMRC meaning of a disclosure letter, because that is where HMRC guidance applies directly. If you are dealing with undeclared rental income, offshore income, or deliberate tax fraud, the type of disclosure, the deadline, and the contents of the letter or disclosure pack matter a great deal.
Why is a Disclosure Letter Important?
A voluntary disclosure can help resolve tax issues with HMRC and may reduce the risk of a more serious civil or criminal response. HMRC states that penalties are usually lower if you disclose errors voluntarily.
In practice, it is not always a simple letter but part of a formal process, such as the Digital Disclosure Service or, for deliberate behaviour, the Contractual Disclosure Facility. Depending on the route, the written submission may take the form of a disclosure, an offer letter, an Outline Disclosure form, or a disclosure report.
What Does a Disclosure Letter Mean in HMRC’s Context?
In HMRC’s context, a disclosure letter refers to telling HMRC about income, gains, or tax that has not been reported correctly. If you have received a letter from HMRC or suspect you have underpaid tax, our HMRC enquiries team can advise on the right disclosure route. Penalties are usually lower when you disclose voluntarily rather than waiting for HMRC to contact you.
According to HMRC guidance, the disclosure process generally follows five key steps, notify HMRC of your intention, disclose full details of the issue, make a formal offer to pay, pay what you owe, and provide further information if requested. This structured process forms what is commonly referred to as a disclosure submission.
The correct route depends on the type of issue involved:
1. Digital Disclosure Service
HMRC’s Digital Disclosure Service is used for disclosures by individuals and companies, and HMRC also allows disclosures through this route for trusts, estates, limited liability partnerships, and those acting on behalf of others to disclose unpaid tax relating to Income Tax, Capital Gains Tax, Inheritance Tax, Corporation Tax, National Insurance contributions, and Annual Tax on Enveloped Dwellings. It can be used where errors arose despite reasonable care, through carelessness, or through deliberate actions.
Note:
HMRC says the Digital Disclosure Service cannot be used for VAT related errors. However, the Worldwide Disclosure Facility guidance separately says VAT liabilities can be flagged on an offshore disclosure.
2. Worldwide Disclosure Facility
If the disclosure involves offshore income, assets, or gains, HMRC requires the use of the Worldwide Disclosure Facility. This applies where the tax issue is linked to matters outside the UK, including overseas bank accounts, investments, or property.
3. Let Property Campaign
Where the undeclared income relates to residential property letting, HMRC provides the Let Property Campaign. This is designed for landlords who have not declared rental income correctly, whether the property is in the UK or overseas.
4. Contractual Disclosure Facility
The Contractual Disclosure Facility applies to serious cases involving deliberate behaviour, where a taxpayer knowingly failed to declare tax or submitted incorrect information. HMRC states that this route is only for tax fraud cases. If HMRC offers CDF and the taxpayer accepts it and makes a full disclosure under the contract, HMRC agrees not to criminally investigate with a view to prosecute for the deliberate behaviour disclosed under that contract.
5. Other HMRC disclosure routes
HMRC’s current guidance also includes specific routes for certain situations. These include disclosures for Research and Development relief claimed in error, unpaid tax on crypto assets, misuse of till systems, and Coronavirus Job Retention Scheme grant repayments. These routes should be used where they apply, rather than the standard Digital Disclosure Service.
When is a Disclosure Letter Used
A disclosure letter is used when there is something important to reveal that affects legal rights, contractual risk, or tax liability. In HMRC practice, common situations include the following.
Unreported rental income
A landlord may have received rent for several years but never registered for Self-Assessment or never included the profits on a tax return. HMRC says landlords with undisclosed residential letting income can use the Let Property Campaign, and once they notify HMRC they normally have 90 days to work out and pay what they owe.
Underpaid tax from earlier years
A person may realise they have not reported income such as freelance earnings, investment gains, or other taxable amounts in earlier years. HMRC provides a service to disclose underpaid tax for both onshore and offshore income not previously declared, along with online calculators to estimate tax, interest, and penalties for straightforward cases.
Offshore income or assets
Someone with overseas bank interest, overseas rental income, or offshore gains may need to use the Worldwide Disclosure Facility. This is particularly relevant where the tax issue is linked in whole or in part to offshore sources or assets.
Deliberate tax fraud
Where a taxpayer knew tax was due and chose not to tell HMRC, or knowingly submitted wrong figures, HMRC treats that as deliberate behaviour. In that situation, the Contractual Disclosure Facility may be the correct route, not an ordinary disclosure.
Business or Property Sale Context
In a sale of a company, or sometimes a property transaction, a disclosure letter can be used to disclose known facts against warranties. That is a private legal disclosure, not an HMRC tax disclosure. The link with HMRC arises only if the disclosed facts reveal tax irregularities, such as undeclared rental income, incorrect filings, or liabilities that need to be reported separately to HMRC.
What Should a Disclosure Letter Contain
The exact format depends on the route used, but a strong HMRC disclosure should cover the essentials clearly and honestly.
Core Contents of a Disclosure Letter
A disclosure to HMRC should clearly include the following key elements:
HMRC Verified Disclosure Deadlines You Need to Know
Deadlines are critical when making a disclosure to HMRC and missing them can affect how your case is handled.
How Penalties are Affected by Disclosure
HMRC penalties depend on the type of behaviour and whether the disclosure is prompted or unprompted. In general, penalties are lower where the taxpayer tells HMRC about the issue before being contacted.
HMRC first determines the behaviour behind the inaccuracy, which can be reasonable care, careless, deliberate, or deliberate and concealed. If reasonable care was taken, no penalty is charged.
For inaccuracies in returns or documents, HMRC applies penalty ranges based on behaviour and whether the disclosure was prompted or unprompted. The final penalty is then reduced based on the quality of the disclosure, often referred to as telling, helping, and giving access to records. The level of cooperation and how quickly the disclosure is made can affect the reduction applied.
The penalty percentage falls within the following ranges:
Type of Behaviour | Unprompted Disclosure | Prompted Disclosure |
|---|---|---|
Reasonable care | No penalty | No penalty |
Careless | 0% to 30% | 15% to 30% |
Deliberate | 20% to 70% | 35% to 70% |
Deliberate and concealed | 30% to 100% | 50% to 100% |
Example,
A taxpayer made a careless error in their tax return and HMRC identified it first, so this is a prompted disclosure.
- The penalty range is 15% to 30%
- HMRC then considers the quality of disclosure
- If the taxpayer fully cooperates, provides records, and explains the issue clearly, the penalty may be reduced within that range
For example, if the additional tax due is £3,000 and the final penalty rate is calculated at 19.5%, the penalty would be £585.
Practical Examples of Disclosure Letters in HMRC Context
Example 1, landlord with undeclared rental income
A landlord has been renting out a property for several years but did not report the income or file tax returns.
Under HMRC rules, this falls under the Let Property Campaign. The landlord must notify HMRC and submit a disclosure within 90 days.
The disclosure letter must include:
- All rental income not previously declared
- Allowable expenses to calculate taxable profit
- Tax due, interest, and penalties
HMRC confirms that only years where tax is due need to be included, so if a year results in a loss, it does not need to be part of the disclosure.
Example 2, offshore bank interest not declared
An individual held money in overseas bank accounts and earned interest but did not include it in UK tax returns.
This must be disclosed using the Worldwide Disclosure Facility, as it involves offshore income.
The disclosure letter should include:
- Details of offshore accounts and income earned
- Tax calculations for each relevant year
- Interest and penalties
- Explanation of the omission
HMRC requires a full disclosure of all undeclared income and gains. The number of years you must include depends on your behaviour, for example reasonable care, careless, or deliberate, and whether the issue involves offshore matters, with disclosures potentially covering up to 4, 6, 12, or 20 years depending on the circumstances.
Example 3, deliberate understatement of income
A company director knowingly reduced business income in accounts submitted to HMRC to pay less tax. This is considered deliberate behaviour, and if it amounts to tax fraud, the Contractual Disclosure Facility (CDF) may be relevant. A person can ask HMRC to consider them for CDF, but HMRC does not have to offer this facility.
- If HMRC offers CDF, the taxpayer has 60 days to accept the offer
- An outline disclosure letter must be provided within that period, explaining the deliberate behaviour
- A full disclosure report must then follow with complete details and calculations
HMRC states that if a taxpayer accepts the CDF offer and makes a full, complete, and accurate disclosure of all deliberate behaviour, it will not carry out a criminal investigation with a view to prosecution for the matters disclosed.
Common Mistakes to Avoid in Disclosure to HMRC
Sending one disclosure for multiple people
HMRC says separate people and separate companies need separate disclosures. A husband and wife with undeclared income cannot simply combine everything into one disclosure.
Using the wrong route
Do not use the Digital Disclosure Service for VAT errors. Do not use CDF for ordinary mistakes that are not fraud. Choose the route that matches the facts.
Missing the deadline
HMRC repeatedly refers to the 90-day disclosure window after acknowledgement for standard disclosure routes, and the 60-day decision period for CDF. Missing these deadlines can put the taxpayer outside the facility terms.
Understating the issue
A partial disclosure is risky. HMRC expects complete cooperation and may ask for evidence, records, and explanations. If records are incomplete, estimates may be used, but they should be reasonable and supported by workings.
Conclusion
A disclosure letter to HMRC is a formal process of telling HMRC about tax that has not been declared correctly and taking steps to put it right. It applies where tax has been underpaid or omitted and forms part of a structured process that may involve routes such as the Digital Disclosure Service, the Let Property Campaign, the Worldwide Disclosure Facility, the Contractual Disclosure Facility, or other HMRC specific disclosure services depending on the circumstances.
The key points are straightforward. Choose the correct HMRC route, provide a full and accurate disclosure, calculate all liabilities properly, and meet the relevant deadlines. A well-prepared disclosure should clearly explain the issue, cover all relevant tax years, include the tax, interest, and any penalties, and make a formal offer to settle. When handled correctly, it can reduce penalties and help resolve tax issues before they escalate further.
FAQs
Yes. HMRC requires you to notify them first that you intend to make a disclosure. At this stage, you do not need to provide full details. Once notified, HMRC will issue a Disclosure Reference Number (DRN), which must be used when submitting your full disclosure and payment.
If you do not come forward, HMRC may identify the issue through compliance checks or data sharing. This can result in higher penalties and, in serious cases, a criminal investigation. Voluntary disclosure is usually treated more favourably and may reduce penalties.
Yes. HMRC allows disclosures to be made on behalf of another individual, company, trust, or estate. However, each person or entity must have a separate disclosure, and you must have the authority to act on their behalf, such as being a tax adviser or personal representative.
HMRC expects payment at the time of disclosure. If you cannot pay in full, you must contact HMRC before submitting your disclosure. They may agree a payment arrangement based on your financial position.
After submission, HMRC will review your disclosure and may request further information. If they are satisfied, they will accept your offer, creating a legally binding agreement. If the disclosure is incomplete or incorrect, HMRC may reject it or carry out further checks.
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