While over 12m tax returns were filed by the deadline, nearly one in 10 taxpayers missed the deadline, leaving 1,071,343 tax returns in the wind, revelaed HMRC figures.

Tax office staff handled 5,409 webchats and 10,483 calls to the helplines which, ‘unusually, were opened on a Saturday to provide extra support to taxpayers on the deadline day’, HMRC said.

With 475,722 taxpayers filing on deadline day itself, there was demand for phone support from around 2% of the self assessment community. 

The last hour on Saturday saw 27,456 people file returns, beating the midnight cut-off at 23.59pm. But most returns were sent between 5-6pm, from the 32,982 people who had likely spent much of the day amassing the necessary information for their return.

In total 11.48m taxpayers filed self assessment tax return for 2024-25 by 31 January avoiding immediate £100 penalty for late submission.

HMRC was expecting just over 12m tax returns and tax payments for 2024-25 tax year by the deadline, leaving 502,000 taxpayers facing an immediate £100 fine.

Official figures from HMRC showed that 12,029,168 self assessment returns were expected and 11,489,825 returns were received by 31 January. 

HMRC is now focusing on Making Tax Digital, issuing a warning to self employed, landlords and sole traders with qualifying income over £50,000 that they will be required to sign up to mandatory MTD for Income Tax from the new tax year on 6 April 2026. In other words, the days of a one-off tax return will be over for these people, with quarterly reporting of income and expenses through accounting software and digital apps only, except in very limited exemption cases.