More than 11.48 million people across the UK filed their Self Assessment tax return by the 31st January deadline, new figures from HM Revenue and Customs have revealed.
HMRC said 11,489,825 returns were received on time for the 2024–25 tax year, with 97.25 per cent submitted online.
Almost half a million taxpayers waited until the final day to file, with 475,722 returns submitted on 31st January alone. Of those, more than 27,000 were filed in the final hour before midnight, while the busiest hour of the day was between 5pm and 6pm.
HMRC helplines were opened on the Saturday deadline day to provide extra support, handling more than 10,000 phone calls and over 5,000 webchats.
Around 12 million people were expected to submit a return, meaning an estimated one million missed the deadline. HMRC has urged anyone who has not yet filed to do so as soon as possible, warning that late filing and late payment penalties will apply.
Penalties start with an automatic £100 fine, even if there is no tax to pay. Further charges increase the longer a return remains outstanding, with additional daily penalties after three months and percentage-based penalties after six and twelve months.
HMRC said customers who cannot pay their tax bill in full may be able to arrange a Time to Pay plan, while online services and the HMRC app remain the quickest ways to file and make payments.
Customers will be able to submit Self Assessment returns for the 2025–26 tax year from 6th April 2026.