More than 1,500 people found time on Christmas Day to submit their online tax returns, HM Revenue and Customs has said.
A total of 1,566 people sent in their tax returns as many households were tucking into their turkey or unwrapping their Christmas presents, marking a 1% increase on the number of people doing this on Christmas Day last year.
The busiest filing hour on Christmas Day was just before lunch, from midday to 1pm, when 144 people hit the send button on their completed return.
This followed 17,000 people who gathered their financial information together and sent in an online tax return on Christmas Eve, marking an increase of almost one fifth (19%) on the same day in 2012.
Boxing Day saw another 4,493 people send their tax return over the internet, showing a slight decline of 4% on Boxing Day last year.
In total, 23,059 online returns were received over the three-day festive period - up by 12% on the corresponding period in 2012.
The deadline for sending in 2012/13 tax returns and paying any tax owed is January 31. But taxpayers who owe less than £3,000 and want HMRC to collect the tax they owe through next year's tax code need to submit an online return by midnight on December 30.
Around 10.9 million people are expected to fill out a Self Assessment return for the 2012/13 tax year. An initial £100 fixed penalty applies to those who do not get their returns in on time, even if there is no tax to pay or if the tax due is paid on time. This can be followed by additional penalties.
People can get help and advice on completing a return by visiting www.hmrc.gov.uk/sa or calling the Self Assessment helpline on 0300 200 3310.
Meanwhile, Halifax said that many of its customers used the festive season to catch up on their finances, with 380,000 people logging on to their bank account on Christmas Day.
Halifax said that the busiest period on Christmas Day was between 10am and noon and more than a third of customers who logged on did so during this time slot.