HMRC revealed a total of 93.68% of more than 11.5 million taxpayers were required to file their 2017/18 tax returns by 11.59pm on 31 January.
The vast majority filed on time, but 700,000 taxpayers missed the deadline.
More than 700,000 taxpayers submitted their tax returns on deadline day, the peak hour for filing was 4pm to 5pm when 60,000 filed.
The number who filed online soared to more than 10.1 million for the first time.
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 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.”
Anyone who failed to submit in time was told to contact HMRC.
The department said it “will treat those with genuine excuses leniently, as it focuses penalties on those who persistently fail to complete their tax returns and deliberate tax evaders.”
It added: “The excuse must be genuine and HMRC may ask for evidence.”