HMRC urges Britons to 'be really careful' as more than 500,000 bogus tax rebates emerge

And, as HMRC is a familiar brand, criminals have been known to abuse it and add credibility to their scams.

If customers can't verify the identity of a caller, HMRC suggests they do not speak to them.

An alert has been shared by Action Fraud ahead of the deadline to renew tax credits next month.

This falls on July 31, meaning customers have until then to notify HMRC of any change in circumstances that could affect their claims.

Renewing can be done online, with customers able to log into GOV.UK to check on the progress of their renewal.