“While the ACCC cannot set or regulate interest rates or fees charged by banks and credit unions, it does maintain an informal oversight of bank fees and charges,” or so says the ACCC. But it’s so informal that it seems to miss a rip-off measured in billions of dollars.

Australia’s banks jealously guard the details of their ballooning fee income and with good reason: they stand to be embarrassed and very vulnerable if details of the not-guite-illegal penalty fees become public.

The Independent overnight published an estimate by Credit Suisse analysts that British banks could be forced to refund 7.2 million quid in “illegal penalty fees” if the Office of Fair Trade rules against them. Reports Saeed Shah:

In the first authoritative study of the charges, banking analysts at Credit Suisse have calculated that high street banks rake in £1.2bn a year from penalty charges. The news will fuel a customer revolt that has taken the banking sector by storm.

Under consumer law, customers are entitled to claim retrospective refunds going back six years if banks are judged to have imposed illegitimate charges on their accounts.

Last year the OFT slashed UK credit card penalty fees to a maximum of 12 pound – about a third of what the banks were charging. If the OFT orders a similar reduction in other bank penalty fees, UK banks are facing an expensive payout.

The UK population is three times Australia’s. It’s rough figuring, but for the sake of the example let’s assume the average Brit runs a little over on his or her overdraft and forgets to pay on time as much as the average Aussie. Let’s also just turn pounds into dollars on a one-for-one basis as the fees seem to be remarkably similar numbers.