Fraudsters posing as police officers have been contacting residents in Hertfordshire in recent weeks.

During June, 26 people were targeted by fraudsters posing as police officers and claiming they were investigating suspicious activity on the victim's bank account.

Fortunately, none of them lost money, however, one elderly victim in Tring was called by a fraudster this month claiming he was investigating counterfeit money at banks and post offices, managing to convince them to hand over £11,000 to a courier.  

Fraudsters often call victims via a mobile or a landline number, posing as a police officer or bank official. The victims are then instructed to put their bank cards and/or money into an envelope and give them to a courier or taxi, which is sent to their home by the offenders. 

In some cases, the victim may be asked to buy goods or vouchers. If bank cards are collected, they can be used later by the offenders to withdraw large sums of money.

The offenders may also ask the victim to disclose their bank details, including their account and PIN numbers, to aid the bogus investigation. 

Detective Inspector Pete Hankins, from the Serious Fraud and Cyber Unit, said: "The number of courier fraud offences reported has been increasing by 20 per cent on last month, with people often losing large sums of money. It's important to remember that police officers or bank officials will never ask you for sensitive information, like a PIN or ask you to purchase high value items to assist them with an enquiry.

"Usually, the intended victim realises the call is not genuine and refuses to part with their personal and bank details. However, these fraudsters can be very persuasive and insistent, which has resulted in some people falling victim to this scam and subsequently losing thousands of pounds."

If you receive a call you are not expecting, you should be suspicious. The vital things to remember are that your bank and the police would:

• NEVER ask for your bank account details or PIN over the phone, so do not disclose these to anyone, no matter who they claim to be.
• NEVER ask you to withdraw money or purchase high value items and send it to them via a courier, taxi or by any other means.
• NEVER ask you to send your bank cards, or any other personal property, to them via courier, taxi or by any other means.

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 dial 101 or report online herts.police.uk/report. In an emergency or if a crime is in progress call 999 immediately. 

Remember, when reporting a suspicious phone call to police, wait at least five minutes before attempting to make the call to ensure you're not reconnected 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.

If you have concerns about your bank account, visit your local branch. 

How to protect yourself:

Remember to follow the above advice. In addition to this, some phone companies offer call screening services that can be effective in blocking marketing cold calls and bogus callers. Contact your phone company and ask about call screening and caller display services. 

How can you help? 

• Please share this information with your older relatives and friends: this crime has a devastating effect on people and we need to raise awareness to prevent further people becoming victims.
• Report any calls you believe are suspicious as we may be able to trace where the calls are originating from. Please remember, to wait at least five minutes before calling police or use a mobile or neighbour's phone.
• Report suspicious activity at cash points. If you see someone spending a long time at a cashpoint, using a number of different cards and have a hood up or their faces covered, contact police immediately. Often offenders will use cashpoints in the early hours.