Late tax returns and reasonable excuses

If HMRC has issued you a tax return for 2024/25 and you miss the deadline, you will be issued with an automatic, initial penalty of £100. After a three-month delay, the penalties really start to escalate.

My tax return is late, what should I do? 

To get your tax affairs in order, you need to either:

1. If you don't think a tax return is required, ask HMRC to withdraw you from self-assessment

If you believe you’re not required to submit a tax return, you must contact HMRC and ask to be removed from self-assessment. If HMRC agrees with you, then you won't need to file a tax return and any late filing penalties issued will be cancelled. 

In the first instance you should contact HMRC online via your HMRC online account. If you cannot do this, you can contact them by phone or post but note that waiting times for calls can be long, especially close to the self-assessment deadline. When calling HMRC, always make a note of who you spoke to and when, and what the outcome is expected to be. 

HMRC is unlikely to remove you from self-assessment if you have been self-employed at any time during the tax year – even if it was only for a short time. 

2. File your return as soon as possible

When your tax return is late, automatic late filing penalties are issued and the later your tax return is filed, the greater the amount of penalties applied. It therefore makes sense to file your tax return as soon as you can. If you need any support getting your tax return filed, contact us so we can help.

Reasonable excuses

If you file your 2024/25 tax return late, you will receive an automatic late filing penalty. If you have a good reason for the delay in filing your return, you may appeal against the penalty.

A reasonable excuse can include:

• your partner or another close relative died shortly before the tax return or payment deadline
• you had an unexpected stay in hospital that prevented you from dealing with your tax affairs
• you had a serious or life-threatening illness

HMRC provides a list of common examples of reasonable excuses for a late tax return on its website.

Late payments

Your tax liability for 2024/25 is due by 31st January 2026. If it is not paid within 30 days of the deadline late payment penalties will start to be charged. Interest begins to accrue from the day after the deadline i.e. 1st February 2026.

If you have a reasonable excuse to file a late tax return and not make a tax payment, your late payment penalties may be waived.

Interest is charged for the entire period the tax is outstanding and this cannot be mitigated.

What's unlikely to be reasonable excuse?

The following aren’t usually accepted as a reasonable excuse for a late tax return:

• You relied on someone else to send your tax return and they didn’t
• Your cheque bounced or payment failed because you didn’t have enough money
• You found the HMRC online system too difficult to use
• You didn’t get a reminder from HMRC

Need more help with your tax return?

TaxAssist Accountants are trusted and experienced at completing self-assessment tax returns for  self-employed professionals, independent business owners, company directors and employed individuals. If you're not receiving the service and support you deserve please talk to us on 01480 592 002 or use our online enquiry form. We offer free initial consultations, advice, and support over the phone or via video call.

Last updated: 4th February 2026