Most letters from HMRC are routine. A tax code change, a payment reminder or a tax calculation. A few ask for records or open a formal check. And some letters claiming to be from HMRC are scams.
So start with two questions. Is it real? And what is it asking you to do? To see why HMRC might write to you, read about what triggers an HMRC investigation.
Quick Answer
Check the letter is genuine first, using HMRC’s list on GOV.UK. Then find the reference, the deadline and what it asks for. Routine letters often need nothing. Letters asking for records or opening an enquiry need a careful reply. Get advice before you send anything.
General guidance only. Your own situation may need specific advice from a qualified accountant.
How Do You Check an HMRC Letter Is Genuine?
Find your letter on HMRC’s list of genuine letters on GOV.UK. Compare what it asks you to do and how to reply. Be wary of any request to email an address not ending in hmrc.gov.uk. If you’re still unsure, call HMRC on a number from GOV.UK, not the letter.
GOV.UK has HMRC’s list of genuine letters sent in recent months. Each entry says what the letter is for and what it asks you to do. Find yours and compare the details.
Watch for these warning signs:
- a request to send details to an email address not ending in hmrc.gov.uk
- pressure to pay today, or threats of arrest
- a request to pay into a personal bank account
- a phone number you can’t find on GOV.UK
Some genuine letters carry a QR code. GOV.UK explains how to check those too.
Did the scam come as an email, text or call? You can report a suspicious email, text or call to HMRC. Forward emails to phishing@hmrc.gov.uk and texts to 60599.
Is Every HMRC Letter the Start of an Investigation?
No. Most HMRC letters are routine. They remind you to file, confirm a payment, change your tax code or show a tax calculation. A formal enquiry is a different letter. It names the return and the tax year it covers, and says what HMRC wants to see.
These letters are usually routine:
- a reminder to file your Self Assessment return
- a statement of what you owe or have paid
- a P2 notice of a new tax code
- a P800 showing tax you’ve overpaid or underpaid
- news about changes to tax rules
Read routine letters anyway. A P800 can mean a refund, or a bill. A wrong tax code can cost you money all year.
Letters That Need Action
Act on any letter that opens an enquiry, asks for records, or sets out tax HMRC thinks you owe. Each kind of check works differently, so read about the types of HMRC investigation before you reply.
What Should You Do First When You Get an HMRC Letter?
Read the whole letter before you act. Note the reference number, the date and any deadline. Work out whether it asks you to do something or just tells you something. Don’t call HMRC until you understand it. Then decide if you can reply yourself.
Work through it in order:
- Check the letter is genuine.
- Read it to the end, not just the first line.
- Write down the reference number and the date.
- Find the deadline, if there is one.
- Note what HMRC asks for, if anything.
- Gather the records it mentions.
A routine letter may need nothing more. Keep it with your tax papers.
An enquiry or a request for records is different. Don’t reply without advice unless you’re sure of every figure.
When Should You Get an Accountant Involved?
Get help straight away if the letter opens an enquiry or asks for records. The same goes for a tax bill you didn’t expect, or a mention of fraud. Your first reply sets the tone for the whole check. Early advice usually costs less than fixing a bad reply later.
Check the scope first. An aspect enquiry looks at one part of your return. A full enquiry covers everything. The letter usually makes this clear.
Two mistakes cause most of the trouble. The first is waiting. Deadlines in enquiry letters are real, and missing them makes things worse.
The second is replying too fast. What you say early shapes the whole check. An accountant makes sure your answers are complete and accurate, and no wider than HMRC asked.
Getting HMRC investigation support early doesn’t make you look guilty. It shows HMRC you’re taking the letter seriously.
What If the Letter Says You Owe Tax You Don’t Agree With?
Don’t pay straight away if you think it’s wrong. Check the figures against your own records first. Then write to HMRC and explain why. If HMRC has made a formal decision, you can usually appeal within 30 days of the decision date. The letter tells you how.
Most mistakes come from missing information. HMRC may not know about an expense, a payment or a change in your work.
If HMRC won’t change its view, you can appeal an HMRC decision. Keep copies of everything you send.
What If the Letter Is About Income You Haven’t Declared?
Take advice before you reply. Coming forward and correcting your returns yourself usually means lower penalties. HMRC treats people who tell it first better than people it catches. Never destroy records once a letter arrives. That makes your position much worse.
Some letters say HMRC has data about income you didn’t declare. It might come from a bank, a letting agent or an online platform.
Check the figures with an accountant before you reply. Then correct what’s wrong. The way you tell HMRC affects the penalty you pay.
Send Us Your HMRC Letter
Not sure what your letter means? Send it to us. We’ll tell you what type it is, whether you need to reply, and what to say.
Get a quote and we’ll send you our current pricing. DASA’s HMRC investigation service handles the reply for you.
This article gives general information about HMRC letters and enquiries. HMRC guidance on genuine letters was checked in October 2026. It’s not tax or legal advice. Speak to a qualified accountant about your own situation.
Last reviewed October 2026 by Raqeeb Marzook, ACCA.
Frequently Asked Questions
How do I know if a letter from HMRC is real?
Find it on HMRC’s list of genuine letters on GOV.UK and compare the details. If unsure, call HMRC on a number from GOV.UK.
Does an HMRC letter mean I’m being investigated?
Usually not. Most letters are reminders, tax code notices or tax calculations. An enquiry letter says so.
What should I do first?
Read it fully, note the reference and deadline, and work out what it asks for before contacting HMRC.
Can I appeal if HMRC says I owe tax?
Usually yes, within 30 days of the decision date. The letter explains how.
Where do I report a scam?
Forward emails to phishing@hmrc.gov.uk and texts to 60599. Report calls through GOV.UK.