Most people who try to reclaim bank account penalty charges get some money back, a study has found.
Most people are successful when they reclaim account charges
A survey for the consumers' association Which? suggests that 85% of people who have demanded a refund have been at least partly successful.
However, only a third of people who believe they may have been overcharged have asked for money to be repaid.
The Which? survey of 2,228 adults found that some were scared of their bank's reaction if they asked for a refund.
"Claiming back unfair bank charges is a simple process that won't take up hours of your time," said Emma Bandey of Which?
"If your bank does not co-operate, you should refer the case to the Financial Ombudsman Service (FOS) as so far the banks have chosen to settle all cases referred to FOS," she added.
In the past year the UK's banks have been deluged with complaints from customers that the charges levied on their accounts for items such as unauthorised borrowing are far too high.
Typically the charges range from £20 to £30 for things such as bouncing a cheque.
The customers have been complaining that the charges are so high they cannot possibly be a fair reflection of the administrative cost of levying the charges and that therefore they are unlawful.
Although the banking industry denies this, no bank has for far decided to contest any refund claim in court and they have been settling out of court instead, often making an offer of full or partial repayment.
The Office of Fair Trading is due to publish a report soon on whether the size of the banks' current account penalty fees is fair.
But in the meantime hundreds of thousands of customers have been downloading draft reclaim letters, from websites such as those of the BBC, Which? and consumer organisations, to send off to their banks demanding a refund of the charges.
One organisation, the Consumer Action Group, says that so far it knows of 6,342 people who have been repaid a combined total of more than £9m by their banks.
So far though, the banks have kept silent about just how many demands they have received and how much money they have paid out, citing "commercial confidentiality" as the reason.
Some banks have even been retaliating against customers by closing their accounts if they ask for a refund.
A quarter of those in the Which? survey who had got round to making a claim said their bank had been unhelpful and unresponsive
"It is terrible how poorly some banks have been treating some customers," said Emma Bandey of Which?
"It is bad enough that they have been levying unfair charges for all this time, but the response from some banks shows that they need to work on their customer service," she said.