Criminals are making fraudulent claims for refunds in a new scam aimed at online self-assessment tax returns.
The warning has come from HM Revenue and Customs (HMRC).
The fraudsters have been acquiring the passwords sent out by HMRC to people who pay their tax online.
Some of the passwords have fallen into the hands of the criminals through scams that persuade taxpayers to reveal their online details or simply through trawls of rubbish bins.
Once the passwords are in the possession of the fraudsters, they are used to submit claims for bogus tax refunds which are then directed to bank accounts other than those of the taxpayers.
A spokesman for HMRC said that self-assessment taxpayers should make sure that they keep their passwords secure and should treat the details as carefully as they would a bank account PIN.
