Skip to Content

How to Appeal an HMRC Self-Assessment Penalty (SA370)

Ready to appeal an HMRC self-assessment penalty? In this guide, you’ll find out how to put together an HMRC tax return appeal using an SA370 form which avoids putting together an appeal letter.

Friendly Disclaimer: Whilst I am an accountant, I’m not your accountant. The information in this article is legally correct but it is for guidance and information purposes only. Everyone’s situation is different and unique so you’ll need to use your own best judgement when applying the advice that I give to your situation. If you are unsure or have a question be sure to contact a qualified professional because mistakes can result in penalties.

1. How to Appeal an HMRC Self-Assessment Penalty

If you have a reasonable excuse, you’ll need to make an appeal to HMRC within 30 days of receiving your penalty notice. If you have missed the 30-day deadline, then you can try to explain the reason for the delay to get your case considered. The way you appeal will depend on whether you want to go online, do it by post or with a phone call to HMRC.

Check here to find out what HMRC considers ‘reasonable’.

It can be helpful to pay your penalty in the meantime because it stops any interest from being charged if HMRC does not agree with your appeal.

1.1 How to Appeal Your Penalty Online

To appeal a tax return penalty you can login into your .GOV account and start the appeal process.

1.2 How to Appeal Your Penalty By Post

If you want to appeal your self-assessment penalty by post, you’ll need to complete a SA370 Form. You’ll need to enter details of the penalty you are appealing, along with your reasonable excuse. It’ll help to have the following information ready before you start filling out the form:

Once you have completed the SA370 form, you’ll need to print and post it to:

Self Assessment,
HM Revenue and Customs,
BX9 1AS.

1.3 How to Appeal Your Penalty By Phone

You can appeal by calling HMRC on 0300 200 3310. They will discuss your appeal with you and tell you if they need you to send any information they need to make a decision. It’ll help to have your UTR number and National Insurance number ready to get through security.

2. How Do You Find Out If Your Appeal Was Successful?

HMRC will write to you to let you know the outcome of your appeal. If your self-assessment appeal has been successful, HMRC will adjust your account for any penalties and interest that have been removed.

If your appeal is rejected, HMRC will write to you to say why they have made their decision and at this point, you’ll need to pay the outstanding penalties and interest. You can appeal again, within 30 days of the rejection, but remember penalties and interest will continue to grow during the time of an appeal unless you have paid the disputed amount.

If you are struggling to pay any outstanding self-assessment penalties and interest, then you can contact HMRC to set up a payment plan.

3. What is a SA370 Form?