More than 700,000 taxpayers rushed to submit their tax returns on deadline day on Thursday – and a similar number now face potential penalties after missing the cut-off point – figures from HM Revenue and Customs (HMRC) show.
HMRC said a new record of 93.68% of self-assessment tax returns were completed by the end of the day on January 31.
More than 11.5 million taxpayers were required to file their 2017/18 tax returns by 11.59pm on Thursday.
The number of taxpayers who filed online soared to more than 10.1 million for the first time, HMRC said.
While the vast majority filed on time, 731,186 taxpayers missed the deadline.
Those failing to file on time face an initial fixed penalty of £100, followed by further potential penalties.
And 735,258 taxpayers filed their returns on January 31. The peak filing hour was 4-5pm when 60,000 returns were received.
Mel Stride, Financial Secretary to the Treasury, said: “It is great to see so many people completing their self-assessment by the deadline.
“Their income tax contributions have helped towards funding the UK’s vital public services including hospitals, schools and the emergency services.”
Angela MacDonald, HMRC’s director general for customer services, said: “Thank you to everyone who filed on time. This year, we had a record numbers of filers completing their tax returns by the deadline.
“And for any customers who are yet to file their returns, please contact HMRC – we are here to help.”
Any taxpayer who has missed the deadline should contact HMRC – which said it would treat those with genuine excuses leniently, as it focuses penalties on those who persistently fail to complete their tax returns and deliberate tax evaders.
The taxman recently released a list of unusual but unsuccessful excuses for why people failed to get their tax returns in on time, including someone who claimed they had been the victim of a witch’s curse.
HMRC has said help will be provided for those who have a genuine excuse for not submitting their return on time – although it may ask for evidence.