When HMRC contacts you, the first reaction is usually panic. But not all HMRC contact is the same — it ranges from a routine compliance check to a full criminal investigation, and the right response depends on what type of contact you’ve received. The biggest risk isn’t HMRC — it’s a scammer pretending to be HMRC, or freezing when you should be acting.

This hub maps every type of HMRC contact, how to verify it’s genuine, your rights during an investigation, and what to do first. Each section gives you the essentials, then links to the detailed guide for the deep dive.

1. The Investigation Spectrum: From Informal Query to Full Enquiry

Not all HMRC contact is an “investigation.” The spectrum runs from a simple question to a criminal prosecution, and the severity determines your response:

Type What it is Timeframe Severity
Informal query A letter asking about a specific figure Weeks Low
Compliance check A formal review of your return 1-3 months Medium
Full enquiry (s.9A) A deep examination of your tax affairs 6-18 months High
Code of Practice 9 Suspected serious fraud 12+ months Very high
Criminal investigation Potential prosecution Years Maximum

Most contacts are at the lower end — informal queries and compliance checks. The higher levels require specific evidence and follow formal procedures. For the full enquiry process and what happens at each stage, see our HMRC investigation guide.

2. Received a Letter from HMRC? Identify What Type

If you’ve received a letter, the first step is to identify what type of contact it is. HMRC letters typically reference:

  • Your UTR or National Insurance number — genuine letters include these
  • The tax year and return being checked — compliance checks specify this
  • What HMRC wants — information, documents, or a meeting
  • The deadline for responding — usually 30 days

If the letter asks you to call a premium-rate number, pay into a non-HMRC bank account, or provide passwords, it’s a scam. For the full guide on identifying and responding to HMRC letters — including what to do if you’ve received an enquiry notice — see our received HMRC investigation letter guide.

3. How HMRC Decides Who to Investigate

HMRC doesn’t pick investigations at random. It uses a system called Connect that cross-references data from banks, property registries, payment platforms, social media, and other government departments to identify discrepancies. Common triggers include:

  • Significant drops in declared income
  • Large expenses claims relative to turnover
  • Property income not matching Land Registry data
  • Platform income (Airbnb, eBay, PayPal) not declared
  • Foreign income or assets not reported
  • Lifestyle indicators inconsistent with declared income

For the full list of triggers and how the Connect system works, see our what triggers HMRC investigation guide.

4. How to Verify HMRC Contact Is Genuine

HMRC scams are widespread. Scammers send fake emails, texts, and letters that look like HMRC but ask for bank details, passwords, or payment to non-HMRC accounts. Real HMRC contact:

  • Comes through your Government Gateway account or by post to your registered address
  • References your UTR or National Insurance number
  • Never asks for your bank details, passwords, or PIN by email or text
  • Never threatens immediate arrest or legal action

If you’re unsure whether contact is genuine, call HMRC directly on a number from gov.uk — never use the number on a suspicious letter or email. For the full guide on spotting fake HMRC emails, texts, and letters, see our is this HMRC email genuine guide.

5. Platform Income Flagged by HMRC

Since 2024, payment platforms (PayPal, Stripe, Airbnb, eBay, Vinted) are required to report seller income to HMRC automatically. If you’ve received income through these platforms and haven’t declared it, HMRC may already know.

Common scenarios:

  • PayPal payments flagged as income when they were friends sending money back
  • Airbnb income not declared on your Self Assessment
  • eBay selling activity that crosses the trading threshold

If HMRC has written to you about platform income, don’t ignore it — but also don’t assume the figure is correct. See our PayPal payments flagged as income guide for what to do, including how to distinguish genuine business income from personal transfers.

6. If You Have Income Abroad You Haven’t Declared

UK tax residents are taxed on worldwide income — foreign rental income, overseas pensions, foreign dividends, and foreign employment income all need to be declared on your Self Assessment. If you have foreign income you haven’t declared, the rules depend on:

  • Whether the income is from a country with a double taxation agreement
  • Whether you’ve been UK tax resident throughout
  • Whether the non-disclosure was deliberate or careless
  • How many years the undeclared income covers

You can make a voluntary disclosure to HMRC, which typically results in lower penalties than if HMRC finds it first. For the full disclosure process, double taxation relief, and penalty ranges, see our undeclared foreign income guide.

7. Your Rights During an HMRC Investigation

You have specific rights during any HMRC enquiry or compliance check:

  • Reasonable time to respond — you don’t have to answer immediately; you can seek advice first
  • Professional representation — you can have an accountant or tax adviser handle the investigation for you
  • Information transparency — you can see the information HMRC is using to make its assessment
  • Right to appeal — you can appeal any assessment or penalty through the independent tax tribunal
  • Privilege — communications with your legal adviser are privileged; communications with your accountant are not (but are still confidential in practice)

HMRC must follow the enquiry process set out in TMA 1970. If they don’t, the enquiry can be challenged. For finding professional representation, see our should I hire an accountant guide.

8. What to Do First When HMRC Contacts You

If HMRC has contacted you, here’s the triage order:

  1. Verify the contact is genuine. Check for your UTR/NI number, call HMRC on a number from gov.uk if unsure. See our is this HMRC email genuine guide.

  2. Identify the type of contact. Is it an informal query, compliance check, or full enquiry? See our received HMRC investigation letter guide.

  3. Don’t respond immediately. You have time — typically 30 days. Use it to seek advice. See our should I hire an accountant guide.

  4. Gather your records. Pull together the returns, receipts, and documents relevant to the enquiry. See our record-keeping guide for what HMRC can ask for.

  5. If you have undeclared income, consider a voluntary disclosure before HMRC finds it. See our undeclared foreign income guide.

  6. If you have a reasonable excuse for any error, document it. This can reduce or eliminate penalties. See our appeal HMRC penalty guide.

The key: don’t ignore it and don’t panic-respond. Verify, identify, seek advice, then respond.

The Bottom Line

  1. Verify the contact is genuine first. HMRC scams are common — call HMRC on a number from gov.uk if unsure.
  2. The investigation spectrum runs from informal query to criminal prosecution. Most contacts are at the lower end.
  3. HMRC uses the Connect system to cross-reference data and identify discrepancies — see our triggers guide.
  4. Platform income is now reported automatically — PayPal, Airbnb, eBay, and other platforms report to HMRC.
  5. Foreign income must be declared — a voluntary disclosure is better than HMRC finding it first.
  6. You have rights — reasonable time, representation, information, and appeal.
  7. Don’t ignore it and don’t panic-respond. Verify, identify, seek advice, then respond.

For the full investigation timeline and what happens at each stage, see our HMRC investigation guide. For estimating penalties if you’ve filed late, see our Self Assessment penalties guide. For the full Self Assessment deadline and payment hub, see our Self Assessment deadlines and payment hub.

Back to Panic Room · Back to Guide