You’ve received a penalty notice from HMRC. Maybe it’s the £100 late filing penalty. Maybe it’s a late payment surcharge. Maybe it’s escalating daily penalties. Whatever it is, you think it’s unfair — you had a genuine reason for being late.
You can appeal. HMRC has a formal appeals process, and they cancel thousands of penalties every year when taxpayers demonstrate a reasonable excuse. The process is free, and you can do it online. Here’s exactly how.
The Golden Rule: File and Pay First
Before you even think about appealing, you must:
- File your return — if you haven’t filed yet, do it now. HMRC will not cancel a penalty for a return that hasn’t been submitted.
- Pay your tax bill — pay as much as you can. If you can’t afford it, set up a Time to Pay arrangement.
You can still appeal the penalty after paying. If HMRC cancels the penalty, they’ll refund the amount or credit it to your Self Assessment account.
According to HMRC’s appeals guidance, the appeal is about the penalty, not the tax. You’re not disputing that you owe tax — you’re asking HMRC to forgive the penalty because you had a valid reason for being late.
What Counts as a Reasonable Excuse?
HMRC defines a reasonable excuse as something that:
- Stopped you from meeting your tax obligation
- Was beyond your control
- You couldn’t reasonably have foreseen
According to HMRC’s reasonable excuse guidance, here’s what’s accepted and what isn’t:
Accepted reasonable excuses
| Excuse | Details |
|---|---|
| Serious illness | Hospitalisation, serious injury, or a mental health crisis that prevented you from filing. You’ll need evidence (hospital letters, doctor’s notes). |
| Bereavement | Death of a close relative or partner shortly before the deadline. HMRC is generally understanding here. |
| HMRC system failure | If HMRC’s online filing system was down on or near the deadline. HMRC usually announces these and may cancel penalties en masse. |
| Postal delay | If you filed on paper and posted it before the deadline but Royal Mail delayed it. You need a certificate of posting (not just a receipt). |
| Fire, flood, or theft | Events that destroyed your records or prevented you from accessing them. |
| Unexpected absence | Being abroad unexpectedly (e.g., a family emergency overseas) with no way to file online. |
| Disability or accessibility issue | If your disability prevented you from filing and HMRC didn’t provide a reasonable alternative. |
| Reliance on a third party | If you gave your records to an accountant well in advance and they failed to file through no fault of yours. (This is harder to prove — see below.) |
NOT accepted as reasonable excuses
| Excuse | Why it fails |
|---|---|
| “I forgot” | HMRC’s position: it’s your responsibility to remember the deadline. |
| “I was too busy” | Being busy is not beyond your control. |
| “I didn’t know the deadline” | Ignorance of the deadline is not a valid excuse. |
| “I found the form too complicated” | HMRC provides guidance and support — complexity is not an excuse. |
| “I didn’t receive a reminder” | HMRC doesn’t guarantee reminders. The deadline is fixed regardless. |
| “My accountant was on holiday” | You’re responsible for choosing a reliable agent. |
| “I didn’t have the money” | For late payment specifically, inability to pay is not a reasonable excuse (but you can set up a payment plan instead). |
| “I was waiting for information” | You should file with estimates and amend later. |
The grey area: reliance on an accountant
If you gave your records to an accountant in plenty of time and they failed to file, HMRC may accept this as a reasonable excuse — but only if:
- You gave them the information well in advance (not a week before the deadline)
- You followed up to check progress
- You had no reason to suspect they wouldn’t file
HMRC will want to see evidence of when you sent your records and any correspondence with the accountant. If you handed everything over on 20 January and your accountant didn’t file, HMRC may argue you left it too late.
How to Appeal: Two Methods
Method 1: Online appeal (recommended)
The fastest way to appeal is through your HMRC Online account.
- Log in to your HMRC Online account
- Go to the penalties section — you’ll see any penalties issued and an option to appeal
- Select the penalty you want to appeal
- Explain your reasonable excuse — be specific: what happened, when, how it prevented you from filing or paying, and when the situation was resolved
- Provide dates — when the excuse started and ended
- Attach evidence — if you have any (doctor’s note, hospital letter, death certificate, etc.)
- Submit
The online form is straightforward and takes 10–15 minutes if you have your explanation ready.
Method 2: Postal appeal using form SA370
If you prefer to appeal by post, use form SA370.
- Download and print form SA370 from gov.uk
- Fill in your details — name, UTR, National Insurance number, the penalty you’re appealing
- Explain your reasonable excuse in the relevant section
- Attach evidence — photocopies, not originals
- Post to HMRC at the address on the form
Postal appeals take longer to process. Allow at least 8 weeks for a response.
How to Write a Strong Appeal
The key to a successful appeal is being specific, honest, and timely. Here’s what HMRC is looking for:
Do:
- Be specific about dates — “I was hospitalised from 25 January to 3 February 2025” is better than “I was ill around the deadline”
- Explain the causal link — “Because I was in hospital, I couldn’t access my records or my computer to file my return”
- Show you filed as soon as you could — “I filed on 5 February, the day after I was discharged”
- Provide evidence — even if HMRC doesn’t always ask for it, including it strengthens your case
- Be honest — if you made a mistake, admit it. HMRC is more lenient with honest taxpayers than with those who fabricate excuses
Don’t:
- Don’t be vague — “personal circumstances” means nothing to HMRC
- Don’t blame HMRC without evidence — “HMRC’s website was down” only works if HMRC actually acknowledged a system failure
- Don’t appeal every penalty — if you genuinely just forgot, don’t fabricate an excuse. HMRC can see your filing history and patterns
- Don’t write a novel — keep it to one page, focused on the facts
Example appeal text
Here’s an example of a well-written appeal for a serious illness:
“I am appealing the £100 late filing penalty for my 2023-24 Self Assessment return (UTR: 1234567890).
On 28 January 2025, I was admitted to hospital with a serious cardiac event. I remained hospitalised until 4 February 2025. During this time, I was unable to access my computer, my tax records, or the internet.
I filed my return on 6 February 2025, two days after being discharged. I have attached a letter from my consultant confirming my hospitalisation dates.
I have been self-employed for 5 years and have never filed late before. I would be grateful if you would consider cancelling this penalty.“
What Happens After You Appeal
Step 1: HMRC reviews your appeal
An HMRC officer reviews your appeal and decides whether to:
- Accept it — the penalty is cancelled, and you’ll receive a confirmation letter. If you’ve already paid, the amount is refunded or credited to your SA account.
- Reject it — the penalty stands. You’ll receive a letter explaining why.
- Partially accept it — HMRC may cancel some penalties but not others (e.g., cancel the initial £100 but not the daily penalties if you delayed filing for months after recovering).
HMRC aims to respond within 45 days, but it can take longer during peak periods (February–March).
Step 2: If rejected, request a review
If HMRC rejects your appeal, you can request an independent review within 30 days of the rejection letter. A different HMRC officer (who wasn’t involved in the original decision) will review your case.
To request a review:
- Log into your HMRC account and select “Request a review”
- Or write to HMRC at the address on your rejection letter
The review is free and takes approximately 45 days.
Step 3: If still rejected, go to the tribunal
If the review also rejects your appeal, you can take your case to the First-tier Tribunal (Tax Chamber). This is an independent body that’s separate from HMRC.
- You must apply within 30 days of the review decision
- The tribunal is free to use
- You can represent yourself — no need for a lawyer
- The tribunal can uphold, reduce, or cancel the penalty
According to HMRC’s tribunal guidance, most cases are resolved without a hearing — the tribunal reviews the written evidence and makes a decision.
What If You Have Multiple Penalties?
If you’ve accumulated multiple penalties (e.g., the £100 initial, £900 in daily penalties, and a 6-month surcharge), you can appeal them all at once. In your appeal, explain:
- Why you were late (the reasonable excuse)
- When the excuse started and ended
- Why you didn’t file immediately after the excuse ended (if there was a further delay)
HMRC may cancel all penalties, or only those that occurred during the period covered by your excuse. For example, if you were ill for 2 weeks around the deadline but then waited 4 months to file, HMRC may cancel the initial £100 but not the daily penalties that accrued after you recovered.
Special Considerations
Late payment penalties vs late filing penalties
You can appeal both, but the criteria differ:
- Late filing: reasonable excuse focuses on what prevented you from filing
- Late payment: reasonable excuse focuses on what prevented you from paying — but “I didn’t have the money” is not accepted. HMRC’s position is that you should contact them to arrange a payment plan.
For late payment, a better strategy is to set up a Time to Pay arrangement rather than appealing — the arrangement suspends the surcharges automatically.
First-time leniency
HMRC sometimes shows leniency for first-time late filers, even without a formal reasonable excuse. If you’ve never filed late before, mention this in your appeal. It’s not guaranteed, but it can help — especially for the initial £100 penalty.
Reasonable excuse for late appeal
If you missed the 30-day appeal window, you can still appeal late if you have a reasonable excuse for the delay. Explain both why you were late filing/paying AND why you were late appealing. HMRC may accept late appeals in these circumstances.
The Bottom Line
Appealing an HMRC penalty is free, straightforward, and worth doing if you have a genuine reason. Here’s the quick summary:
- File your return and pay your tax first — you can’t appeal a penalty for an unfiled return
- Check if you have a reasonable excuse — illness, bereavement, HMRC failure, events beyond your control
- Appeal online through your HMRC account — it takes 10–15 minutes
- Be specific and honest — dates, evidence, causal link
- If rejected, request a review — then take it to the tribunal if needed
- Don’t fabricate an excuse — HMRC can check your filing history and medical records
Even if you’re not sure your excuse qualifies, it’s worth appealing. HMRC reviews each case individually, and the worst that can happen is they say no.
If you’ve missed the filing deadline entirely, see our missed deadline guide. For the full breakdown of what penalties cost, see what happens when you file late. If you can’t afford your tax bill, see what to do when you can’t afford your HMRC tax bill.