Scammers are persuading their victims to buy iTunes vouchers as payment for supposed debts, police have revealed.

The con involves fraudsters posing as agents from legitimate organisations such as HM Revenue and Customs.

Victims are told they have outstanding debts which require immediate repayment.

They are then advised to repay these "debts" by buying iTunes vouchers from their local supermarkets and passing on the serial number to the scammers.

One man in his 80s, from Alloa, paid out £3300 after being threatened with an arrest warrant if he failed to pay up.

The con was only thwarted after staff at his local supermarket became concerned and prevented him from buying more vouchers.

Police said their action had saved the man from losing thousands more pounds.

Details of the scam have now been passed to supermarkets across the UK in a bid to prevent anyone else falling victim to the fraudsters.

Forth Valley Division's crime prevention officer PC Bryan MacKie was responsible for alerting shop staff to the con.

He said: "Working with local supermarkets, we developed preventative measures such as a till prompt which asks staff to make further checks with the customer if they are trying to buy vouchers in bulk, or over a certain value."

Tesco, Asda, Morrison's, Sainsbury's and the Co-op all took up the initiative locally and the prompts are now used at stores throughout the UK.

Mr MacKie said: "Within weeks of these measures being introduced, an elderly man was prevented by staff at a supermarket in Falkirk from losing £250 to scammers through the purchase of iTunes vouchers.

"All of the stores have been very supportive of putting mechanisms in place to try and prevent their customers from falling victim to these scams."

The officer said it was "really encouraging" that supermarkets across the UK had picked up on the scam and were intervening when necessary. "In January, we were made aware that staff at a store in Northallerton prevented three people from being defrauded of a total of £1800 because of this," he added.

Police continue to advise people to exercise caution when dealing with callers who claim to be collecting debts.

They advise anyone who receives a suspicious call to hang up immediately and contact local officers on 101.