Around a million people missed the deadline for filing their self assessment tax return, HM Revenue & Customs (HMRC) has said.
Of the returns, 97.25% were submitted online, with 316,000 paper returns filed.
There were 475,722 taxpayers who waited until the final day on 31 January, with 27,456 submitting their details in the last hour.
The busiest hour for submitting a return on deadline day was 17:00 to 17:59, when 32,982 people filed.
HMRC advisers dealt with 5,409 webchats and 10,483 calls to its helplines on 31 January. The tax authority originally said the phone lines wouldn’t be open because it was a Saturday but then reversed that decision and announced they would be.
Those who missed the deadline face an initial £100 fixed penalty.
After three months, additional daily penalties of £10 per day are imposed up to a maximum of £900.
After six months, it’s a further penalty of 5% of the tax due or £300, whichever is greater.
After 12 months, there’s another 5% or £300 charge, whichever is greater.
Myrtle Lloyd, HMRC’s chief customer officer, said:
“Thank you to the millions of people and agents who filed their Self Assessment tax return and paid any tax owed by 31 January.
“Anyone who missed the deadline should file their return as soon as possible, as penalties and late payment interest may be charged.
“HMRC digital channels are always the quickest and easiest way for people to sort their tax affairs. Search ‘Self Assessment’ on GOV.UK to find out more.”