Tens of thousands of taxpayers were still awaiting their self-assessment tax calculations this week with just days to go before the 31 January deadline. Some advisers estimated that as many as 500,000 people were still waiting.

Taxpayers who send their self-assessment returns to HM Revenue & Customs before the end of September are sent a calculation of what they owe, saving them having to work out their liability.

Thousands of these filers have now received reminders to pay their tax, but have not been issued with a payment calculation.

With just days to go before the 31 January deadline, the taxman has apologised for the oversight but warned that taxpayers will still have to pay up on time. HMRC has promised to have updated calculations sent out to all affected by the end of the week.

'Some SA Statements due to be sent to customers in December 2007 were not issued. We are also aware that some of those customers have subsequently received one of our general payment reminders with a blank payment slip. We are very sorry for the inconvenience this may have caused you and/or your clients,' HMRC said in a statement.

Further reading:

Read the full HMRC statement here

HMRC: file self-assessment returns early to avoid strike