HM Revenue and Customs (HMRC) said that at the start of yesterday (January 31st), 1.3 million people had yet to file their returns, with 400,000 set to do so before the deadline passed.
Anyone who missed yesterday's cut-off point will now be handed a £100 fine, but will need to submit their details ahead of it being three months late or face further penalties.
While figures on how many people filed their returns on time have not yet been published, a spokesman for HMRC said: "We are pleased that more and more people file online each year."
Additional £10 daily penalties - up to a maximum of £900 - will be issued for any return that is three months late, while additional fines are issued at six and 12 months, too.
Posted by Thomas Fletcher