A letter from HMRC saying it has information about your overseas bank account or foreign assets is alarming. But it is not necessarily a formal investigation, yet. Knowing exactly what type of letter you have received, what HMRC knows and what your options are in the response window can be the difference between a clean resolution and an escalating full enquiry.
On this page
What a nudge letter is
An HMRC offshore nudge letter is a non-statutory compliance check. This means it is not a formal enquiry under s9A Taxes Management Act 1970, nor a discovery assessment, nor a statutory information notice. HMRC has data, most commonly from the Common Reporting Standard, suggesting that you hold or have held offshore assets or income that may not have been fully declared on your UK tax return. The letter is a prompt to voluntarily correct any non-compliance.
Because it is non-statutory, you are not legally compelled to respond to a nudge letter in the way you would be compelled to respond to a statutory information notice. However, ignoring it is rarely wise, HMRC will escalate and the escalation route leads to a formal investigation with significantly higher penalties and much less control for the taxpayer.
Crucially, a nudge letter that prompts a voluntary disclosure before HMRC has formally opened an enquiry allows that disclosure to be classified as “prompted” under the offshore penalty framework, which is substantially more favourable than the “HMRC-initiated” classification that applies once a formal investigation is under way. See our offshore penalty framework guide for the impact of this distinction on penalty rates.
Why HMRC sends nudge letters
HMRC sends nudge letters because they are more cost-effective than immediate formal investigations. When CRS data triggers a match showing apparent undisclosed foreign income, HMRC has two options: immediately open a formal enquiry (resource-intensive, slow) or send a nudge letter (quick, inexpensive and effective at generating voluntary disclosures).
The nudge letter strategy also has a secondary penalty law effect that benefits HMRC. Where a taxpayer receives a nudge letter and then voluntarily discloses, the disclosure is classified as “prompted” rather than “unprompted”, meaning higher minimum penalties than the taxpayer would have faced had they come forward on their own initiative without any HMRC contact. In this sense, HMRC’s nudge letter programme both recovers tax at low cost and ensures that the resulting penalty rates remain at “prompted” levels or above.
For the taxpayer, the practical implication is clear: if you have offshore non-compliance you have been meaning to deal with, acting before any HMRC contact is always the best position. The moment a nudge letter arrives, the unprompted window has closed.
The main types of offshore letter
Not all offshore compliance letters from HMRC are “nudge” letters. Understanding which type you have received is important because the appropriate response and the available options differ.
CRS data match letter
The most common type. HMRC’s letter typically states: “We have received information that you hold or have held a financial account overseas.” It references the Worldwide Disclosure Facility and asks you to check your returns and, if necessary, make a disclosure. This is a standard nudge letter, non-statutory, with a response window (typically 30 days).
Undeclared foreign income letter
A slightly more targeted letter: “Our records suggest you may have foreign income that has not been declared on your tax return.” HMRC is more specifically pointing at income items (interest, dividends, rental income from overseas property) rather than simply account existence. The legal status is still non-statutory, but it indicates HMRC has cross-referenced income data more closely.
Offshore asset letter (post-2021)
Following extensions to CRS reporting that capture more data on non-financial assets and passive non-financial entities, HMRC has been issuing letters specifically referencing offshore assets (including property data obtained through non-CRS routes such as European land registries) and trust structures. These letters often accompany wider reviews of the taxpayer’s overall offshore position.
Requirement to Correct follow-up letters
In the years following the September 2018 RTC deadline, HMRC issued follow-up letters to taxpayers who had previously received nudge letters but had not responded. Some of these letters explicitly referenced Failure to Correct penalties. Although the mass RTC follow-up campaign has largely concluded, HMRC continues to issue individual FTC letters where its data identifies pre-2017 non-compliance that was not corrected.
Typical content of a nudge letter
While HMRC uses several different template letters for offshore nudges, most share the following elements:
- The concern: a brief description of the information HMRC holds, typically that it has received data under CRS showing a financial account, income or asset in a named or unnamed territory
- A timeframe: usually 30 days to respond, make a disclosure or contact HMRC
- Reference to the WDF: details of the Worldwide Disclosure Facility (or a URL) as the recommended route for making a disclosure if non-compliance is identified
- A warning: HMRC typically states that if it does not receive a satisfactory response, it may open a formal enquiry and higher penalties may apply
- A response form or contact address: HMRC may include a form to complete confirming either that you are compliant (with supporting explanation) or that you are making a disclosure
Notably, nudge letters typically do not disclose the specific account details or figures that HMRC holds. This is deliberate, HMRC is prompting the taxpayer to self-identify the issue rather than having HMRC establish the figures.
What to do on receipt
The following steps represent the appropriate response to an HMRC offshore nudge letter:
Step 1: Do not ignore the letter
Ignoring an offshore nudge letter is the single most common mistake. HMRC will not assume the matter is resolved by silence. Non-response virtually always leads to escalation to a formal enquiry, at which point the WDF is no longer available and penalties are significantly higher. The response window, typically 30 days, is not a deadline by which you must have resolved everything, but it is a deadline by which you must have done something.
Step 2: Check the underlying facts
Before deciding on a course of action, you need to know whether there actually is an error in your tax position. Review your Self Assessment returns for the years in question and check whether you have declared:
- All interest from foreign savings accounts
- All foreign dividends and investment income
- All gains on disposal of foreign investments
- All rental income from overseas property
- All foreign pension income
If everything has been correctly declared, you may simply need to write to HMRC confirming compliance with supporting evidence.
Step 3: If there is non-compliance, use the WDF promptly
If reviewing your returns reveals undisclosed offshore income or assets, the appropriate route is to use the Worldwide Disclosure Facility promptly. Register the notification on the Gov.uk portal, which opens your 30-day window to prepare and submit the full disclosure. Using the WDF after a nudge letter gives you a “prompted” disclosure classification, which is substantially better than waiting for a formal HMRC enquiry. See our full guide: The Worldwide Disclosure Facility Explained.
Step 4: If there is no non-compliance, respond in writing with evidence
If you are satisfied that your returns are correct, respond to HMRC in writing within the response window. Confirm that you have reviewed the relevant years and that the income or assets concerned were correctly declared. Provide specific evidence, references to the relevant Self Assessment return entries, copies of foreign bank statements showing the income or certificates of foreign tax deducted at source that match declared figures. A clear, evidenced response will typically close the matter.
Step 5: Take specialist advice before responding if the position is complex
If your offshore position involves multiple accounts, trust structures, corporate holdings, historic years or any doubt about whether all obligations have been met, take specialist advice before responding. An incorrect or incomplete response to a nudge letter can inadvertently provide HMRC with evidence of non-compliance or result in an inadequate disclosure that HMRC later expands into a full investigation.
The risk of ignoring the letter
If HMRC’s nudge letter receives no response, the typical escalation path is:
- A second nudge or follow-up letter, sometimes more explicitly threatening
- Opening of a formal enquiry under s9A TMA 1970 for income tax self-assessment or issue of a discovery assessment under s29 TMA 1970 for earlier years
- Issue of statutory information notices requiring the production of documents and records
- In serious cases, escalation to HMRC’s Fraud Investigation Service and consideration of Code of Practice 9
Once HMRC has opened a formal enquiry, the behaviour classification in the penalty framework shifts from “unprompted” or “prompted” to an HMRC-initiated investigation, eliminating the penalty reductions that would have been available through voluntary disclosure. Depending on the territory category and the behaviour, the difference in effective penalty rate between a prompted WDF disclosure and an HMRC-initiated enquiry without any voluntary cooperation can be 50 to 100 percentage points of the tax owed.
For significant offshore positions, this is a very large sum of money, all avoidable by acting within the response window.
Frequently asked questions
Is a nudge letter the same as being under investigation?
No. A nudge letter is a non-statutory compliance check, not a formal enquiry under s9A TMA 1970 or a discovery assessment. HMRC has not yet formally opened an investigation; it is prompting voluntary compliance. However, if you do not respond satisfactorily, HMRC will typically escalate to a formal enquiry, at which point the situation becomes an active investigation. The distinction matters enormously for the penalties that ultimately apply. See our offshore penalty framework guide for the difference between prompted and HMRC-initiated penalty rates.
Does responding to a nudge letter increase my penalty?
Not if you respond correctly. Responding with evidence of compliance involves no penalty at all. Using the WDF after a nudge letter results in a “prompted” disclosure penalty rate, higher than unprompted, but substantially lower than the penalties following an HMRC-initiated formal investigation. What increases your penalty is non-response (which leads to escalation and an HMRC-initiated classification) or responding in a way that provides evidence of non-compliance without making a proper structured disclosure through the WDF.
What if I genuinely had no idea I owed UK tax on overseas income?
Genuine ignorance does not eliminate the liability, UK residents are taxable on worldwide income regardless of awareness. However, it is very relevant to the penalty. If HMRC accepts that the failure was careless (rather than deliberate), the penalty rates are substantially lower. A genuine and reasonable misunderstanding, particularly where it is supported by reliance on professional advice, may support a reasonable care defence reducing the penalty further. The facts and circumstances of each case matter. Specialist advice helps to present the behaviour correctly in the context of a voluntary disclosure. See our main offshore guide for more on the reasonable excuse and reasonable care defences.
How quickly do I need to respond to a nudge letter?
Most nudge letters give a 30-day response window. You should take specialist advice and form a plan of action within the first week, not the last. If you are going to use the WDF, you need to register the notification and submit the full disclosure within the 30-day WDF submission window after notification. Leaving everything until day 28 leaves no room for complications. If your position is genuinely complex and you need more time to calculate the disclosure, a specialist adviser can communicate with HMRC to explain the position and manage expectations, but this should be done proactively, not after the window has closed.