Fraudsters have tried to convince vulnerable people to withdraw cash by posing as police officers.

Bank staff were forced to intervene on Thursday when a woman from Chedgrave attempted to withdraw cash, after a man claiming to be from Hammersmith Police contacted her by phone.

The fraudster told the woman that her bank account had been hacked, and that she needed to withdraw money to rectify it.

But when she spoke to bank staff, they advised her the incident was fraudulent, and ensured no money had been taken.

The following day a second woman, from Wymondham, received a phone call from a man claiming to a detective from Norfolk Police.

He asked the woman to confirm her address, which she did.

However, at this point her carer intervened, and asked the man to provide his collar number.

When he was unable to do so she terminated the call.

Det Sgt Chris Archer, from Norfolk Police, said: "This is a known method used by suspects to commit frauds and encourage vulnerable victims to withdraw large sums of money from their accounts. Fortunately, no money has been handed over in either incident but we clearly want people to be vigilant to such scams."

"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."

Norfolk Police warned people in the county to always ask anyone claiming to be a police officer to provide their identification number and police force.

A spokesman said: "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."

Officers added that police and banks would not ask for personal details such as account numbers or PIN numbers over the phone.

Anyone with concerns about such calls should contact Norfolk Constabulary on the non-emergency number 101 or 999.