More than eight out of ten people have successfully reclaimed money from their banks due to unfair overdraft charges, new research claims.
According to Which?, 85 per cent of its 2,200 survey respondents had a portion of the money they claimed for refunded.
But the consumer watchdog insists that the proportion should be closer to 100 per cent if customers persisted with their banks.
Emma Bandey, personal finance campaigner at Which?, said: "Claiming back unfair bank charges is a simple process that won't take up hours of your time.
"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."
According to Which?, more than two-thirds of Britons with bank accounts have been affected by unfair overdraft charges.
Its research also reveals that of the customers that do not attempt to reclaim money, one in five do so out of fear over how their bank would react.
A similar proportion believes the process would be too complicated while a third simply does not know how.
"It is terrible how poorly some banks have been treating some customers. 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," added Ms Bandey.