Cyber criminals are reportedly stealing money by hacking into the systems of HM Revenue & Customs to hijack self-assessment records.
The Sunday Times reports that HMRC intercepted approximately 17,000 attempts to make fraudulent or incorrect tax repayment claims, worth nearly £100m last year.
However, it says HMRC has been unable to fend off all the attacks, with one major accountancy firm conceding that 12 of its own clients had been targeted.
Fraudsters are using “phishing” scams to obtain personal information, such as the details used by taxpayers to access the HMRC systems, primarily through deceiving people into handing over the information directly.
Criminals then access the tax system to alter earnings information so that HMRC offers a repayment, with money then transferred into newly created bank accounts.
HMRC told the paper it is “one of the most phished organisations in the world”, but declined to specify how many successful attacks had taken place, warning instead that online login details to HMRC systems are “like gold dust to fraudsters”.
The report comes just a week after HMRC’s 31 January self-assessment deadline, which saw more than nine million taxpayers file self-assessment details.
An HMRC spokesman says: “Our online services have not been hacked and remain secure. We take our obligations around protecting customer data extremely seriously and have systems in place to review suspicious activity and monitor access to accounts.
“It’s only right that when appropriate we contact taxpayers and any agents acting to alert them to any concerns.”