HM Revenue and Customs (HMRC) has issued a stark warning to millions of households across the UK: the deadline for submitting self-assessment tax returns is fast approaching, with significant financial penalties for those who miss it.
The January 31 Deadline and Immediate Penalties
The critical cut-off is 11.59pm on January 31. Failing to file your return by this time, without an agreed delay or a valid 'reasonable excuse', will trigger automatic penalties from HMRC. The most immediate consequence is a £100 fixed penalty, which applies even if your return is just one day late, from February 1 onwards.
Myrtle Lloyd, HMRC’s Director General for Customer Services, urged people not to delay: "The Self Assessment deadline is less than one month away, and thousands have already paid their tax bill via the HMRC app. It is quick and easy to do, and you can also see your payment history."
What Counts as a 'Reasonable Excuse'?
HMRC does allow you to appeal a penalty within 30 days if you believe you have a legitimate reason for missing the deadline. The tax authority provides a specific list of circumstances it may accept, including:
- The death of a partner or close relative near the deadline.
- An unexpected hospital stay preventing you from dealing with your tax affairs.
- A serious or life-threatening illness.
- Technical failures, such as software or computer issues while preparing an online return, or problems with HMRC's own online services.
- Events like fire, flood, or theft that stopped you from completing the return.
- Postal delays that were outside your control.
- Delays related to a disability or mental health condition.
Crucially, HMRC states that the following are NOT considered reasonable excuses: a cheque bouncing, a payment failure due to insufficient funds, finding the system too difficult to use, not receiving a reminder, or simply making a mistake on your return.
Late Payment Charges and Your Options
It is vital to remember that the deadline applies to both filing your return and paying any tax you owe. Separate penalties apply for late payment. If you pay your tax late, you will incur further charges of 5% of the unpaid tax at 30 days, six months, and 12 months.
For those concerned about paying their bill, HMRC may offer a solution. If you owe less than £30,000 and meet eligibility criteria, you can often set up a 'Time to Pay' arrangement to spread the cost. Payment can be made via the HMRC app, online through GOV.UK, by direct debit, or from your bank account.
The tax office reports a surge in app use, with almost 340,000 people having used the HMRC app to pay their Self Assessment tax since April 6, 2025—an increase of over 130,000 compared to the same period last year.
Taxpayers are reminded to use the official self-assessment tax calculator on GOV.UK to estimate their bill and, when filing online, to ensure they click the final 'Submit' button and wait for the confirmation email.
