An urgent scam warning has been issued to millions of tax credits claimants.
The dangerous scammers are claiming to be HM Revenue and Customs (HMRC) urging them to hand over their cash.
New figures have revealed that in the 12 months to April 30, HMRC responded to more than 1,154,300 referrals of suspicious contact from the public.
Of these, more than 576,960 offered bogus tax rebates.
This is an issue that is particularly important for tax credit claimants, who can expect to receive the remaining annual renewal packs in the post this week.
Some may fall victim to a sophisticated scam while looking out for genuine correspondence from HMRC.
The criminals urge those targeted to share their personal details or even transfer money for a bogus overpayment.
In the year leading to April 30, HMRC has worked with telecoms companies and Ofcom to remove more than 3,000 malicious telephone numbers and with internet service providers to take down over 15,700 malicious web pages
HMRC responded to 443,033 reports of phone scams in total, 135% up on the previous year.
Many scams actually mimic genuine Government messages in order to appear authentic and reassuring.
Some scams use HMRC branding and logos, or include links to the official HMRC address or phone number.
Myrtle Lloyd, HMRC’s Director General for Customer Services, said: "We're urging all of our customers to be really careful if they are contacted out of the blue by someone asking for money or bank details.
"There are a lot of scams out there where fraudsters are calling, texting or emailing customers claiming to be from HMRC.
"If you have any doubts, we suggest you don’t reply directly, and contact us yourself straight away.
"Search GOV.UK for our ‘scams checklist’ and to find out ‘how to report tax scams'."
