More than 4,800 self assessment scams have been reported since February 2025, according to data released by HMRC.
The tax authority says scammers are using persuasive and threatening tactics to target people when they are more likely to receive correspondence from HMRC. The scammers send fake tax demands or attempt to pressurise people to hand over personal information.
In the last 10 months, taxpayers have reported more than 135,500 HMRC-related scams, including 29,000 scams referring to fake tax refund claims.
HMRC is reminding customers to be vigilant and check whether the email, SMS message or phone call claiming to be from HMRC is genuine on GOV.UK.
Lucy Pike, HMRC's Chief Security Officer, said:
'Millions of people file a tax return each year and scammers mimic HMRC to try and catch unsuspecting victims out.
'I'm urging people to stay vigilant and if any emails, text messages or phone calls appear suspicious – don't be lured into clicking on links or sharing your personal information – report it directly to HMRC. Just search 'report an HMRC scam' on GOV.UK to find out more.'