£100 penalty for late self-assessment tax returns

Self-assessment taxpayers have a week to send in their electronic tax returns for the 2009-10 tax year.

Missing the 31 January deadline incurs a £100 penalty as well as interest charges on any unpaid tax. However, people looking to file their tax returns electronically for the first time may have already missed a 21 January deadline for registering on the HMRC website. Those who have missed this earlier deadline are urged to call their tax offices and make payment of any unpaid tax before 31 January. "There is a fixed penalty of £100 for filing a personal tax return late, although this can be avoided by ensuring that any 2009-10 tax is paid in full by 31 January," Andrew Shaw, from the chartered accountants Kingston Smith, said.

Each year, an estimated 900,000 people miss the self-assessment deadline and face a penalty. But the wide adoption of filing electronic tax returns is gradually reducing this number. Last year, a record 6.4 million people filed online, up from 5.8 million in 2009. This year, so far, HMRC has received 4.6 million online returns, compared to 10 years ago, when 39,000 were filed online. But a flurry of late returns may push the total filing online above the 2010 figure.