Top bosses of major retailers are being urged to share details of a ‘prolific’ scam with their staff base as a last line of defence against fraudsters.

HMRC has written to many of them today (February 10) following a high-profile iTunes phone scam which targets both vulnerable and elderly people and cons them out of thousands of pounds.

The scammers cold-call their victims and impersonate HMRC members of staff, telling them they owe large amounts of tax which can only be paid through Apple’s iTunes vouchers.

Angela MacDonald, HMRC’s director general of customer service, said: “It’s really reassuring to see reports of supermarket staff, off their own back, taking action to keep customers safe. Raising public awareness is the best safeguard against this vicious scam.

“Supermarket staff are often the last line of defence against these fraudsters. That’s why I’ve written to the chief executives of major UK retailers to urge them to make their staff aware of this scam so they can help protect unsuspecting customers.”

It is after victims of the scam visit their local shop to purchase these vouchers that they then read out the redemption code to the scammer, who then use it to purchase high-value items at their expense.

There have been more than 1,500 reports of the scam since 2016, with the vast majority of people conned being over 65 years old and averaging a financial loss of £1,150 each, according to figures from Action Fraud.

The highest ever loss was reported last week when an 81-year-old man lost £20,000 when he was targeted by fraudsters.

HMRC says it is taking daily action to crack down on current scamming operations.