Form SA370: Appeal a Self Assessment Penalty in 30 Days

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Get the official SA370

SA370 is published free by HM Revenue & Customs. Download it from the official page, then use the walkthrough on this page to complete it.

Open the official SA370 page on GOV.UK →

Quick answer: If HMRC has charged you a Self-Assessment late-filing or late-payment penalty, Form SA370 (or your online account) lets you appeal — normally within 30 days — if you have a “reasonable excuse” that lasted throughout the delay.

HMRC issues automatic penalties for filing or paying Self-Assessment late. If something genuinely outside your control caused the delay, you can appeal — and many appeals on a clearly-stated reasonable excuse succeed.

What is Form SA370?

HMRC’s appeal form for Self-Assessment penalties (late filing and late payment). You can appeal on paper with SA370 or through your HMRC online account.

Who needs it & when

Anyone charged a Self-Assessment penalty who has a reasonable excuse — e.g. serious illness, bereavement, a HMRC service failure, or another event beyond their control — and who has since filed/paid.

Deadlines & key rules

Appeal must reach HMRC within 30 days of the penalty notice (late appeals need a reason).
You generally must have filed the return / paid before appealing.
The “reasonable excuse” must have existed throughout the period of delay and you acted without unreasonable delay once it ended.

How to appeal it — step by step

Identify the penalty and date; confirm you’re within 30 days.
Set out your reasonable excuse with dates and any evidence.
Complete SA370 (or appeal online), one penalty per appeal where required.
Submit; if rejected, ask for a statutory review or appeal to the tribunal.

How Chris helps

Tell Chris what happened and Chris drafts your SA370 appeal around your reasonable excuse, to a high, professional standard — you check, sign and submit. Not a law firm.

See it done — an SA370 penalty appeal, drafted in minutes

An appeal against an HMRC Self-Assessment penalty, built around your reasonable excuse to a high, professional standard — Chris drafts it in minutes. Scroll the sample below.

DRAFTED BY CHRIS · sampleSCROLL ↓

Helen Carter · UTR 1234567890

To: HMRC, Self Assessment

Appeal against late-filing penalty — tax year 2024/25

Dear HMRC, I appeal against the £100 late-filing penalty dated 5 March 2026 on the ground of reasonable excuse.

I was admitted to hospital on 18 January 2026 for emergency surgery and discharged on 9 February 2026, and was unable to deal with my affairs throughout the 31 January deadline. I filed my return on 20 February 2026, as soon as I was able. Medical evidence is enclosed.

The excuse existed throughout the period of delay and I acted without unreasonable delay once it ended. I ask that the penalty be cancelled.

Yours faithfully, Helen Carter

Illustrative sample with fictional names and details. Chris drafts yours from your own facts; you check, sign and submit.

Draft your appeal →

Last reviewed: June 2026 · England & Wales (HMRC is UK-wide) · CIC No. 16566612 — not a law firm.

Form content and official guidance on this page are reproduced or adapted from material published by HM Revenue & Customs on GOV.UK. Contains public sector information licensed under the Open Government Licence v3.0. eLitigant CIC is independent and is not affiliated with, or endorsed by, HM Revenue & Customs or any government department. Always check the current official form on GOV.UK before you file.

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