By following the steps in this guide, you may find yourself £100 better off

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Nearly two-thirds of bank customers hit with "unfair" overdraft charges have yet to reclaim their money, according to Which?.

Research from the campaign group indicated that 64 per cent of consumers who have been charged penalties of up to £39 a time could be missing out on hundreds of pounds in returned cash.

Of those who have already made a claim, as many as 85 per cent have been successful in getting at least some of their money refunded and our simple, three-part plan can help you to join the thousands who have reclaimed bank charges.

The Office of Fair Trading issued a ruling last April that saw credit card companies slash their penalty charges, and now the watchdog has turned its attention to bank charges on current accounts. While it is investigating charges, the banks are clearly on a warning about their excessive charges.

Penalty charges on current accounts can include a variety of fees, such as for exceeding an agreed overdraft, bouncing a cheque or paying an item that takes an account into the red. Customers can be charged as much as £38 if a cheque is bounced or a direct debit payment is refused, even if the transaction takes the customer's account over the agreed limit by as little as £1.

Similar charges are made by the banks when customers go over their overdraft limits. And many customers have been further incensed when a bank's penalty charges have taken them over their overdraft limit - resulting in further bank charges.

When the OFT examined credit card charges, it ruled that £12 was a justifiable level of charge for such penalties.

The credit card issuers quickly responded by reducing their charges in line with the OFT findings. Now the banks are expected to do much the same, after the watchdog issues its ruling later this month.

Which? has taken legal advice and come up with a set of form letters for bank and credit card customers to help to reclaim excessive charges levelled on their accounts going back over a period of six years.

For the average customer who might have incurred two or three penalty charges a year, using the form letters could see them receive a refund from their bank of around £100.

"Which? feels default charges should be proportionate and reflect the administration costs involved," said the organisation in response to the OFT announcement on credit cards. "They should not be, as they are now, arbitrary figures picked to make the most money out of unsuspecting customers."

Consumers can continue to challenge banks for default charges applied to unauthorised overdrafts while the charge calculations are investigated by the OFT. While there is no guarantee that the banks will accept the claims, this simple three-step plan could help to save you around £100 and potentially much more.

Just click Next below to follow our plan for reclaiming your bank charges, complete with form letters you can copy and send to your bank.