Conmen pretending to be police officers targeted seven, mostly elderly, St Albans residents alleging fraudulent activity on their bank accounts.

The conmen claimed to be from Hammersmith Police Station and suggested that the victims’ cards had been recovered and they needed to confirm their bank details.

St Albans Safer Neighbourhood Sergeant, Ann-Marie Owen, said: “Fortunately most residents were suspicious, put the phone down and contacted police by dialling 999 from their mobiles so they were no longer connected to the conmen on their landlines.

“In one instance, the caller asked the victim to withdraw a substantial amount of cash from the bank and keep it safe for two days.”

The calls took place last Thursday, August 21, and Friday, August 22, evenings but no reports were received over the weekend.

Sgt Owen urged potential victims never to withdraw money and send it to them via a courier, taxi or any other means with the same advice applying to bank cards or other personal property.

She went on: “If you are not happy with a phone call and are suspicious of the conversation you have with the caller then please end the call and contact police via the non-emergency number, 101.

“It’s important to remember, when reporting a suspicious phone call to police, to wait at least five minutes before attempting to make the call. Make sure that there is a dialing tone to enable you to phone out so you are not re-connected to the offender.

“Alternatively, use a mobile phone or a neighbour’s phone or test your landline by phoning a friend or relative first, to ensure you aren’t still unwittingly connected to the offender.”