Over one million self assessment taxpayers missed the filing deadline at midnight on 31 January, according to data published by HMRC.
A record 11.5 million taxpayers did file their 2022/23 self assessment tax returns by the deadline.
HMRC's figures also showed that 1.1 million missed the deadline.
The final day saw 778,068 beat the clock to complete their return.
The peak hour for filing on 31 January was between 16:00 and 16:59 when 61,549 taxpayers submitted their returns. 32,958 filed between 23:00 and 23:59.
HMRC has urged anyone who missed the deadline to submit their tax return as soon as possible – late filing and late payment penalties apply for those who failed to submit by the deadline. It stated that there are many ways to pay, including online, using the HMRC app, by bank transfer or via a Time to Pay payment plan.
Myrtle Lloyd, Director General for Customer Services at HMRC, said:
'Thank you to the millions of self assessment customers and agents who met the deadline. Anyone who has yet to file and is concerned that they cannot pay in full may be able to spread the cost of what they owe with a payment plan. Search 'pay your self assessment' on GOV.UK to find out more.'
Internet link: HMRC press release