HMRC reports that 890,000 people failed to meet the deadline, which was up on last year's figure of 708,840, but well below the 1.6m recorded in 2010. In total 11.13m self assessment returns were due by 31 January of which 4.28m (42%) were submitted in January with 979,256 (9.6%) filed on 30 and 31 January.

This will give HMRC an immediate windfall of £89m in late penalty charges.

Late filers will face penalties, including an initial £100 penalty. After three months there are additional daily penalties of £10 per day, up to a maximum of £900. After six months, a further penalty of 5% of the tax due or £300, whichever is greater is levied followed after 12 months, by another 5% or £300 charge, whichever is greater.

Ruth Owen, HMRC's director general of personal tax, said: ‘This is another record-breaking year for self-assessment, with 210,000 more people filing their returns on time than last year.’

However, Owen cautioned that anyone who had failed to file could see fines increasing fast if they did not complete the forms quickly.

‘If you're one of the minority who missed the deadline, you still need to get your tax return to us as soon as possible, to avoid further penalties and interest mounting up,’ Owen said.

People with a genuine reason for not filing should contact HMRC to ensure they do not incur more penalties. There are further details at www.gov.uk/self-assessment-tax-returns or the Self Assessment helpline on 0300 200 3310 (open 8am to 8pm, Monday to Friday, and 8am to 4pm on Saturday).