Multiple police forces across the country have reported an increase in the number of banking customers falling victim to fraudsters in recent weeks.
Organised criminals are targeting vulnerable people, persuading them to either withdraw and hand over cash or to transfer money into bank accounts.
Victims, who are almost always elderly, will usually be contacted by telephone at home and often have complete faith in the false information provided by the fraudsters.
They tend to claim to be from the police, Action Fraud or a fraud department from a bank or mobile phone company.
Claims that the victim's bank account has been compromised are commonplace, together with instructions to quickly transfer funds to what’s purported to be an alternative account provided for them.
Detective Inspector Debbie King said: "It's so important that people take steps to protect their elderly relatives and friends by continually warning them of the dangers.
"The stories being sold to victims by fraudsters are, of course, wide and varied.
"The criminals prey on people’s willingness to help, or the fear of losing money unless they act quickly.
"It might be claims that hackers are attacking their internet or bank account.
"One of the more elaborate tales is claiming to be from the bank’s fraud department and asking the victim to test the branch staff by going undercover as a mystery shopper.
"There have been other examples where the victim is told they are needed to assist the police in a 'sting' on corrupt staff by withdrawing cash from the bank; bringing it home and awaiting a 'police' arranged courier to collect it from them as evidence.
"The victims are often told how to act, for example to discretely keep their mobile phone line open whilst in the bank, enabling the fraudsters to monitor what is being said.
"They may be told to avoid eye contact with branch staff and not to talk about what they are doing.
"They may also be prepped with answers to any questions surrounding the reason for a big money transaction; funding a family member’s wedding perhaps, or gifting cash to a relative, using it for a holiday, to buy a car or for home improvements.
"In some instances, victims are instructed to make repeat trips to branches to withdraw or transfer funds.
"Even when they realise they have been a victim of fraud, some people are too embarrassed to tell anyone and their health can suffer as a result.
"This is why it is so important we have these conversations with each other - and especially with our elderly friends and relatives.
"The bottom line is that legitimate organisations would NEVER call an individual and ask them to withdraw or transfer money."
To report a fraud, visit www.actionfraud.police.uk.
Alternatively, you can call 0300 123 2040.
In an emergency, always call 999.