One of Britain's biggest online banks has warned thousands of customers to limit their use of cash machines because of the growing risk of fraud.
Letters have been sent to thousands of customers
First Direct has advised some customers to consider getting enough money out in a single withdrawal to last all week.
But the police have warned that carrying large amounts of cash creates more opportunities for crime.
ATM fraud rose to £39m last year, according to the cheque and plastic crime unit set up by police in London.
First Direct, part of the HSBC group, says regular cash machine users are most at risk from fraudsters.
It has written to the 10% of its customers who use cash machines most regularly, warning them of the risks.
"You can withdraw up to £500 at one time from a cash
"You may find it more convenient to make a single withdrawal to cover your cash requirements for the day or even for the week ahead," said the letter.
The bank also suggests using debit cards and getting cashback from retailers as alternatives to cash machines.
But Detective Inspector Tony Thomas from the cheque and plastic crime unit said he was surprised to learn of First Direct's advice.
"I don't support it. We should not be giving in to these criminals. Yes, we need to be careful but we need to keep it in perspective," he told BBC Radio 5 Live.
"To carry large amounts of cash around with us is creating new risks."
First Direct spokeswoman Annette Spencer said the letter was advisory only and not prescriptive.
She said some customers used cash machines several times a day and were being advised to think about their use.
"We recognise the risks associated with taking cash out once a week," she told BBC News Online.
Criminals use various methods to target cash machine users, including attaching card "skimming" devices to ATM machines which copy cardholders' details.
Another method includes inserting a device which traps the card inside the machine, to be removed and used later to withdraw cash.
In other cases, thieves watch over ATM users' shoulders to get their Pin number, before stealing their card.