A number of bogus emails are being issued saying they are from HMRC and advising the receiver that they are due a tax refund. I received one myself only last week.
HMRC never communicates by email directly with taxpayers on their personal tax affairs.
If you receive an email saying you are due a tax refund please delete it, do not be tempted to reply and certainly do not give away your personal bank account details.
I do know of one unfortunate individual who was taken in by a scam email and passed on their bank details to subsequently find that the scammers had emptied their bank account. The bank subsequently repaid the money so nothing was lost but it must have caused some stress.