Penalty of £100 kicks in on 1 March for those who failed to pay by 31 January, and rises after three, six and 12 months

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More than 1 million people have missed the deadline to file self-assessment tax returns and face a penalty starting at £100, HM Revenue & Customs has said.

Taxpayers had until midnight on Friday to submit returns online. HMRC said 11.5 million people had done so in time, but that 1.1m returns were outstanding.