Cold callers are continuing to pose as police officers and prey on vulnerable elderly people, demanding they withdraw huge sums of cash.

Now, a senior police officer is urging members of the public to be vigilant when answering the phone.

It comes after a number of incidents in the Great Yarmouth, Gorleston, Potter Heigham and Norwich areas.

Detective Inspector Matt Dyson, from Great Yarmouth CID, urged for residents to be aware of the scam.

He said: 'We're urging members of the public, particularly the elderly who are being targeted, to be vigilant to cold calls made on the telephone.

'Genuine police officers of staff would never approach residents and ask for cash withdrawals to be made or for people to purchase items on their behalf.

'I would ask people with vulnerable relatives, friends or neighbours to make sure they are aware of this type of scam.'

Scammers have been making cold telephone calls to vulnerable residents, claiming to be police officers and requesting they withdraw large sums of money before arranging to meet with officers.

It has been known for suspects to request cash is posted or for residents to purchase high value goods, and to then meet the people purporting to be officers to hand over the goods.

In some cases victims have been defrauded of thousands of pounds.

In one case someone lost £9,000, while in another case a victim purchased a high-value watch which was handed over to suspects.

Organisations like Action Fraud offer victims of fraud a place to go to in order to report crime and get advice and support.

A spokesman for the charity said: 'We are committed to providing the best service possible to victims of fraud and those who need advice.

'Our partnership with the charity Victim Support is central to this commitment and this is why everyone who reports a fraud to us has the option to receive support from the charity afterwards.'

Anyone with concerns about such calls should contact Norfolk Police on the non-emergency number 101 or 999 if a crime is in progress quoting Operation Mendip. Or call Action Fraud on 0300 123 2040.