The number of scam emails offering fake tax refunds hit an all-time high last month.

According to HM Revenue & Customs, a record 83,000 such phishing attempts were reported in September.

The phishing deluge has continued into October, with taxpayers alerting HMRC to 10,000 scam attempts in a single day this month.

The scam emails tell the recipient they are due to receive a tax refund and then ask for bank account or credit card details. They often begin with a sentence such as: "Following a review of your fiscal activity you are due a refund of tax of £XXX."

Those who are duped into handing over their details risk having their bank accounts drained and credit cards maxed-out. HMRC has also warned that some fraudsters also sell their victims' details on to other criminal gangs.

This is the third warning the HMRC has issued about online tax refund scams this year. The first was during the run up to the 31 January deadline for filing tax returns online. At the time HMRC said it had received reports of 11,000 scam emails in the previous nine months.

The second warning came in July, ahead of the deadline for tax credit renewals, when the number of reported scams hit 15,000 over the previous 12 months.

"What we have found in the past is that when it is coming up to a specific deadline within the tax year there is an increase in the number of scam emails," an HMRC spokeswoman said.

The latest version of this scam comes in advance of the 31 October deadline for filing paper tax returns. HMRC says it originates from a number of different websites, which operate for 20 minutes before changing their domain name.

Last month's spike in scam emails may not entirely be due to an increase in criminal activity, however. The growth in reported phishing scams is likely to be partly down to people following HMRC advice and forwarding the offending emails to the department's online reporting facility, the HMRC spokeswoman said.

Anyone who receives a tax refund phishing email is encouraged not to open it, send it to phishing@hmrc.gsi.gov.uk for investigation and then delete it from their computer.