Self-assessment: Glitches and new rules mean more taxpayers at risk of £100 deadline fine

Self-assessment taxpayers are being urged to get their skates on and file their returns by the 31 January deadline, or face a £100 fine.

This year, more people may be in line for an automatic fine for missing the deadline as, for the first time, HM Revenue & Customs is only accepting returns filed online through its website. In previous years, HMRC has accepted paper and emailed returns up until the end-of-January deadline; this time, any such returns had to be in by 31 October 2008.

"Some may be caught out ... and miss the deadline. It's essential to plan and not leave things to the last minute," Chas Roy-Chowdhury, head of taxation at the Association of Chartered Certified Accountants, said.

Anyone leaving it to the last minute may also come unstuck because they will need a password to use the HMRC website to file a tax return, and that can take a week to obtain. Also, HMRC's website has been known to crash in the run up to the deadline. "There will be more traffic going through the HMRC website this year so who knows what will happen," Mr Roy-Chowdhury said. "Best file early and, if you do try close to deadline and can't, then print off any error messages to show HMRC that you've tried. Doing this should prevent a fine."