According to a report from Financial Fraud Action UK (FFA UK), almost a quarter of Brits have received a cold call from someone claiming to be from a bank or similarly trustworthy organisation, requesting personal or financial information. Around four in ten say that they find it challenging to tell the difference between a genuine and fraudulent call.

Vishers takes advantage of the fact that landlines have a 'two minute switch' which requires both parties to hang up for a call to end. Crooks tell victims to hang up and call their bank but stay on the line to gain access to the valuable data.

Almost a third of the 2002 quizzed for the report receive at least 10 cold calls per month, with 41% suspecting that a call was fraudulent or suspicious. Those over 50 are most at risk, with nearly half having received a fraudulent or suspicious cold call.

DCI Dave Carter, head of the dedicated cheque and plastic crimes unit, told Finextra that the rise in vishing is in large part down to the success of the security measures put in by banks in recent years, particularly chip and PIN. This has forced crooks to target what they consider the "vulnerability in the system, which is the consumers themselves".

Says Carter: "Always be wary of cold callers who suggest you hang up the phone and call them back. Fraudsters will keep your phone line open by not putting down the receiver at their end. Remember that it takes two people to terminate a call so try and use a different phone line if you are asked to ring back."