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 3 months: £10 per day (up to £900).
• After 6 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.
• 6 months.
• 12 months.

Late payment interest will also be charged, which is currently at 7.75% per annum.

If you need help filing your tax return, please get in touch with Lyndon Howes on 023 8046 1253 or email Lyndon Howes.