Understanding Your Appeal Rights: What HMRC Letters Actually Mean

You've received a letter from HMRC. It says you owe money, or they've changed your tax, or they're charging you a penalty. Your first question is probably: can I challenge this?

The answer depends on what kind of decision HMRC has made—and whether you act quickly enough.

Not Every HMRC Letter Can Be Appealed

HMRC sends millions of letters each year. Most are routine—statements, reminders, requests for information. These don't have appeal rights because there's no "decision" to challenge.

But some letters contain appealable decisions. These include:

• Penalties for late returns, late payments, or inaccurate returns
• Tax assessments where HMRC has calculated what you owe
• Closure notices ending an enquiry into your tax return
• VAT decisions about registration, assessments, or penalties
• Tax credit and Child Benefit decisions, which go through "mandatory reconsideration" and the Social Security and Child Support Tribunal, not the tax tribunal, so the rest of this guide does not apply to them (the High Income Child Benefit Charge is income tax and does follow it)

If your letter contains an appealable decision, it will say so. Look for a section headed "Your rights" or "How to appeal" near the end of the letter.

One letter looks like an assessment but is not: a "Determination of tax due", HMRC's estimate of your tax when you have not filed a return. It cannot be appealed; filing the return replaces it (see can you appeal an HMRC determination?).

The 30 days Deadline

Here's the critical part: you usually have 30 days to respond. This is 30 days from the date printed on the letter—not 30 days from when you received it.

If your letter sat in a pile for a week before you opened it, that week counts against you.

Miss the deadline and HMRC will treat their decision as final. You can still ask for a late appeal, but you'll need a good reason for the delay, and acceptance is not automatic.

Your Two Options

When you disagree with an HMRC decision, you have two main paths. For income tax, capital gains tax, corporation tax and the other direct taxes, both start the same way: you first appeal in writing to HMRC within 30 days (section 31A TMA 1970 for income tax and capital gains tax; paragraphs 34 and 48 of Schedule 18 FA 1998 for corporation tax; section 222 IHTA 1984 for inheritance tax), and then choose between a review and the tribunal. For VAT and other indirect taxes, you choose straight away (see Direct Tax vs Indirect Tax below).

Option 1: Ask HMRC for a Review

A review is an internal HMRC process. A different officer—one who wasn't involved in the original decision—looks at your case again. They work in HMRC's Solicitor's Office and Legal Services, separate from the team that made the decision.

HMRC has 45 days to complete the review. At the end, they'll either:

• Uphold the original decision (no change)
• Vary the decision (change it somewhat)
• Cancel the decision entirely

Reviews are free and usually faster than going to the tribunal. If you disagree with the review outcome, you still have the right to appeal to the tribunal—you haven't given anything up. See our detailed guide to HMRC's internal review process for what to include and what the statistics show.

Option 2: Appeal to the Tax Tribunal

The First-tier Tribunal (Tax Chamber) is independent of HMRC. A judge (or panel) will hear both sides and make a decision. If you are not sure what the tribunal actually is, our explainer What Is The Tax Tribunal? covers who decides, what it can and cannot do, and how it differs from a court.

There is no fee to appeal—filing costs £0. You don't have to ask for a review before going to the tribunal. For VAT and other indirect taxes you can appeal to the tribunal directly; for direct taxes you can notify the tribunal as soon as you have appealed to HMRC. But for most disputes, trying a review first makes sense—it's quicker, costs nothing, and over 12,000 HMRC decisions are changed through reviews each year. See our step-by-step guide to appealing for exactly how to file.

The Third Path: Review, Then Tribunal

Most people choose this route:

1. Ask HMRC for a review (for direct taxes, once you have appealed to HMRC)
2. Wait for the outcome (45 days)
3. If you still disagree, appeal to the tribunal within 30 days of the review conclusion letter

This gives you two chances to resolve the dispute before involving a tribunal.

Direct Tax vs Indirect Tax: A Key Difference

The process differs slightly depending on what type of tax is involved.

For direct taxes (Income Tax, Capital Gains Tax, Corporation Tax, National Insurance, Inheritance Tax):

• You appeal to HMRC first
• HMRC may try to resolve things informally
• If not resolved, HMRC offers you a review
• You have 30 days from the date of HMRC's letter to accept the review or go straight to tribunal (section 49C TMA 1970; for Inheritance Tax, section 223C IHTA 1984)
• If you do neither, HMRC's view is treated as settling your appeal, and after that you can go to the tribunal only with its permission

For indirect taxes (VAT, excise duty, customs duty):

• HMRC automatically offers a review in the decision letter itself
• You have 30 days to accept the review or appeal to tribunal (section 83C VATA 1994)

The deadlines are the same. The differences are where you start (with HMRC for direct taxes) and when the review is offered.

Do You Have To Pay While You Challenge It?

If HMRC has sent you a tax assessment, you may be wondering whether you need to pay before the dispute is resolved. For direct taxes, you can apply to postpone payment of the disputed amount while your appeal is pending—but interest continues to accrue from the original due date regardless. For penalties, HMRC will normally not enforce payment while an appeal is outstanding.

See the payment and postponement section of our step-by-step appeal guide for how this works in practice.

What If You Miss the Deadline?

For direct taxes and their penalties, ask HMRC in writing to accept a late appeal if you have a "reasonable excuse"—something that genuinely prevented you from responding in time. Examples might include serious illness, bereavement, or postal problems.

HMRC must accept your late appeal if they are satisfied you had a reasonable excuse and asked without unreasonable delay once it ended. If they refuse, you can ask the tribunal to allow a late appeal. For VAT, excise and customs duty, HMRC cannot accept a late appeal, so you ask the tribunal directly. Either way, the tribunal will want you to explain the delay and show you acted as soon as you could.

The safest approach: don't miss the deadline. If you need more time to prepare your arguments, you can appeal within 30 days and provide full details later.

What To Do Now

If you've received an HMRC decision letter:

1. Check the date on the letter and count 30 days forward
2. Find the appeal section—usually near the end, headed "Your rights" or "How to appeal"
3. Decide your approach: review, tribunal, or accept the decision. For direct taxes, either of the first two starts with a written appeal to HMRC
4. Respond in writing before the deadline, even if you're still gathering information—include your name, tax reference number, the decision you're challenging (with the date and reference from the letter), and why you disagree

You can appeal online for some decisions (like Self Assessment penalties). For others, you'll need to write to the address on the letter. Our step-by-step appeal guide covers exactly what to include and where to send it.

Further Reading

• Can You Appeal An HMRC Determination Or Dispute Your Tax Return? — estimated bills when you haven't filed, amending a return, and overpayment relief
• What Is The Tax Tribunal? How The First-tier Tribunal (Tax Chamber) Works — what the tribunal is, who decides, and what it can and cannot do
• Disagree with a tax decision or penalty — GOV.UK overview
• How to get a review of an HMRC decision — detailed review guidance
• Appeal to the tax tribunal — tribunal process

This article is for informational purposes only and does not constitute legal or tax advice. For advice specific to your situation, consult a qualified tax adviser, accountant, or solicitor.