An elderly woman was conned out of almost £7,000 by a gang of 'contemptible' fraudsters.

The 86-year-old received a call claiming her bank card had been used to buy counterfeit Euros.

A man who said he was a police officer told her she would have to buy 4,000 Euros [£3,423] from a bureau-de-change, so officers could check if they were counterfeit.

The victim agreed to do this twice and on each occasion the cash was collected by a courier from her home address at Walpole Highway, near King's Lynn.

Today, a family member said: 'It's contemptible. People phone, they cold call and if they think they've got someone they can work on, they work on them.

'She's very, very upset. She's very embarrassed. She's gutted.

'It's a huge financial blow to her. It's absolutely enormous, at very least it's the vast bulk of her life savings.'

The male courier who visited the woman's house is described as being black, around 6ft 1in tall, of a slim build, aged in his 20s and wearing hi-vis clothing.

Similar incidents have been reported throughout the county and it has been known that suspects 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.

Investigating officer Det Con Nichola Lane from King's Lynn CID, urged for residents to be vigilant to this scam.

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

'Genuine police officers or 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.'

Officers have this advice:

Never give out personal information about your bank account to anybody over the phone.

If someone calls claiming to be a police officer, ask for their identification number and police force. Hang up and call 101 using a different phone.

If you can't use a different phone, wait at least five minutes before calling back. A genuine police officer will not mind waiting while you check.

Police and banks will never ask you to give out personal details such as account numbers or PIN numbers.

If you have given out information which could compromise your bank account security in any way, call your bank to cancel your cards as soon as possible.

Never hand over money to someone at the door to be sent off elsewhere.

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