Missed the Self Assessment deadline? Follow LITRG’s four steps

While HMRC has said that it received 11.48 million tax returns by the 31 January self assessment deadline, it also says that around one million customers missed the cut-off date¹.

Failing to meet the self assessment deadline carries an automatic £100 late filing penalty, with further penalties at stake the longer the return remains outstanding. If the return is left outstanding for a year, these penalties can exceed £1,600 – on top of separate penalties and interest for late paid tax².

LITRG has published four steps to help get these taxpayers back on track³. These are:

1. Checking whether a return is even needed: In some cases, taxpayers may have received a notice to file a 2024/25 tax return even though they no longer needed to do one. If that is the case, they may be able to have their return (and late filing penalties) cancelled.
2. Filing outstanding returns as soon as possible: If the return is required and cannot be cancelled, swift action should be taken to submit the return and avoid further late filing penalties.
3. Paying the tax that is due: Paying tax as soon as possible will prevent additional penalties for late payment. Payment plans may be possible for those unable to pay their tax in full – though interest will continue to apply to late paid tax, even where a payment plan is in place.
4. Appealing a penalty: If taxpayers have a reasonable excuse for not meeting the deadline (such as illness or bereavement), they usually have 30 days to appeal any penalties charged.⁴

LITRG is also reminding taxpayers that Making Tax Digital (MTD) for Income Tax⁵ applies from this April for taxpayers with gross self-employment and/or property income of more than £50,000 declared on their 2024/25 tax return., Therefore if you are self-employed or a landlord it is particularly important that you finalise your 2024/25 tax return as soon as possible to give yourself some time to get ready for MTD if necessary.

Antonia Stokes, LITRG Senior Manager, said:

“Missing the self assessment deadline can feel daunting or worrying, and some people might be unsure how to put things right.

“But there are some practical steps people can take. This includes working out whether a return was even needed in the first place. If it was, then it is better to act now by filing the return and paying the tax, penalties and interest charges that are due. Payment plans are available to help people who might not be able to settle their tax bill in full.

“If they have what is called a reasonable excuse, it might even be possible to appeal the penalty, but they will still need to file their tax return as soon as possible.”

On the implications for taxpayers impacted by Making Tax Digital, Antonia Stokes added:

“For those taxpayers who will be part of Making Tax Digital, it has never been more important for them to have their tax affairs in order.

“If you meet the income requirements for Making Tax Digital based on your 2024/25 tax return data, and you do not have an exemption,⁶ you will be expected to sign up for this new regime before April 2026 and be ready to follow the new rules from then too – even if you haven’t received a letter from HMRC to tell you to do so.”

Notes for editors

1. HMRC press release: 11.48 million beat the self assessment deadline, 3 February 2026.
2. See LITRG website for more information: Tax penalties and interest
3. See LITRG news article for further detail: Missed the self assessment deadline? Don’t panic – here’s what to do next
4. You can read more about what might be considered a reasonable excuse on the LITRG website. There is also information about how to appeal a penalty on GOV.UK. Although penalties have a 30-day appeal window, HMRC may consider late appeals in some cases.
5. See LITRG’s Making Tax Digital information hub for more information.
6. Some people will be exempt from MTD, or will be able to apply for an exemption in certain circumstances. You can read more about exemptions here.