Banks and credit card companies are facing criticism over the charges they levy against their customers.
The chief executive of the Banking Code Standards Board, Seymour Fortescue, will tell bankers that such charges help fuel the industry's poor public image.
UK banks are said to raise about £400 million a year from charges, which is thought to be far higher than the costs incurred from late payments.
"If I were still a poacher I'd have a real job defending these charges," the banking regulator is expected to say.
"They do not appear to be related to the costs, they frequently hit those least able to pay them and they generate great resentment," he told The Guardian.
Despite his criticisms, Mr Fortescue is expected to say that self-regulation of the banking industry is working. Check out how to get the best deal from your current account.
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