HMRC said it expects 12.1 million tax returns to be filed this year, with around 55% of individuals already completed. According to the authority, more than 6.2 million chose to submit online.
In addition, almost 18,000 customers filed their tax returns on 1 January, with 1,943 completing their returns between 3pm and 3.59pm.
Once customers have completed their tax return, and know how much tax is owed, they can set up their own payment plan to help spread the cost of their tax liabilities, up to the value of £30,000.
Customers can use the “self-serve Time to Pay” facility to set up monthly direct debits online, with interest due to be applied to any outstanding balance from 1 February 2021.
Karl Khan, interim director general for customer services at HMRC, said: “In what was a very difficult year for many, we are grateful to the 55% of our customers who have already submitted their returns.
“HMRC is ready to offer support to those who are yet to file their returns or are worried about paying their tax bill, but they must act now so we can help before the deadline.”