PENSIONERS have been warned to be on their guard against a sophisticated bank fraud scam.

Criminal gangs have masterminded a new "no hang up" scam to steal elderly and vulnerable people's life savings.

The warning was sparked by two cruel crooks who conned a 75-year-old woman from Lanarkshire out of more than £10,000.

She was phoned, out of the blue, and told that her bank suspected her account had been compromised.

The worried victim was then asked to call the bank back, using the phone number on the back of her debit card.

Having dialled the bank's number, she assumed she was speaking to bank staff - but the cons had kept the line open and stole a five-figure sum of cash.

Police sources said scammers have worked this type of "courier fraud" into a "fine art".

A Police Scotland spokeswoman said: "Officers have been made aware of a courier fraud incident in Lanarkshire in which a 75-year-old woman was advised to transfer money into a rogue account.

"This can happen anywhere.

"The best way to avoid becoming a victim of this type of fraud is to remember that your bank or the police will never ask for your bank card and PIN over the phone.

"You should never divulge these to anyone, at any time."

Most people are unaware that a phone line can remain open for up to five minutes after the handset has been put down by the person receiving the call.

This allows fraudsters to stay on the line to impersonate a victim's bank.

Police have launched a probe into the Lanarkshire incident, which happened earlier this week.

No futher details about the victim have been released in a bid to protect her identity.

Officers are hunting a man and a woman -who both posed as bank workers - to swindle the elderly lady's savings.

Tony Blake, from a nationwide anti-fraud unit, warned about scammers who specifically target pensioners.

He said: "Some people might find it hard to believe, but these people are convincing, and they specifically pick people who are elderly, isolated and vulnerable.

"Pensioners are being conned out of hundreds of thousands of pounds."

Anyone with any concerns about courier fruad is asked to contact Police Scotland on 101.