One Million Miss the Tax Return Filing Deadline

HMRC has estimated that around a million people missed the 31 January 2026 Self Assessment tax return filing deadline.

It confirmed that 11.48 million people filed their tax return on time, with most people filing online.

As usual, there was a significant rush on deadline day itself with nearly half a million people filing on 31 January, including more than 27,000 in the final hour before midnight. The busiest hour was between 5 pm and 6 pm, when almost 33,000 returns were submitted.

Despite this, it seems that a million people missed the deadline altogether.

If you missed the deadline

Anyone who still needs to file should do so as soon as possible. HMRC applies a fixed £100 late filing penalty immediately, even if no tax is owed.

Further penalties apply the longer the return is outstanding:

• After three months: £10 per day (up to £900).  
• After six months: 5% of the tax due or £300, whichever is higher.  
• After 12 months: another 5% or £300.

There are also penalties for paying tax late - 5% of anything unpaid at 30 days, six months and 12 months - plus interest.

If you need help filing your tax return, please get in touch. We would be happy to help you.

What’s coming next

Making Tax Digital for Income Tax will start from April 2026 for many sole traders and landlords.

From 6 April 2026, Making Tax Digital (MTD) for Income Tax becomes mandatory for sole traders and landlords with qualifying income over £50,000.

MTD involves keeping digital records and sending quarterly updates to HMRC.

If you need help getting ready for MTD, please get in touch. We can help you with all aspects of MTD, including choosing suitable software, bookkeeping and submitting the quarterly updates and end of year return.

See: https://www.gov.uk/government/news/1148-million-beat-the-self-assessment-deadline 

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