Detectives are urging residents to be on guard against fraudsters posing as police officers, following a series of thefts and attempted thefts.

The incidents are the latest in a series of crimes in which mainly elderly people are targeted and tricked into revealing their bank details or handing over bank cards or large sums of cash.

More than 780 similar thefts and attempted thefts have been reported in Essex since January 2013 with more than £400,000 stolen.

A police spokesman said: "Police and banks would never ask for your bank account details or PIN number over the phone, so do not disclose these to anyone, no matter who they claim to be.

"They would never ask you to withdraw money and send it to them via a courier, taxi or by any other means.

"They would never ask you to send your bank cards, or any other personal property, to them via courier, taxi or by any other means."

A police taskforce that was set up to tackle phone scams will feature on BBC's Watchdog programme, tonight at 8pm.