The Office of Fair Trading's (OFT) threat to report banks to the Competition Commission jeopardizes the way that current accounts have worked for decades.

Customers who manage their accounts badly are penalised heavily so that the rest of us have free banking. The banks maintain that the system is fair, and customers who don't go into the red may well agree.

After all, why should someone who manages their account carefully pay for the "reckless" behaviour of others? If customers do not want to incur charges, say the banks, they should not breach their overdraft limits.

The banks argue that if the OFT pushes for overdraft charges to be lowered the free banking we all take for granted will disappear. Do you really want to pay to withdraw cash from an ATM, pay for statements, pay for direct debits like our continental and American peers?

There is merit in this defence of the status quo, but there is a catch. The charges, of £25 or more for slipping into an unauthorised overdraft, are punitive. Some banks, such as Barclays, have admitted as much by recently cutting their fees.

Even worse, the charges tend to fall with disproprotionate frequency on low earners who can least afford to pay them.

No doubt some of those who regularly pay bank charges are reckless. But it is more likely that they simply do not have much money going into their bank accounts.

Often going overdrawn is the first sign of debt trouble. At a time when thousands of low-income families are struggling to cope with soaring food and energy bills, bank charges may be all it takes to push them over the edge.

If you are a "good" customer reluctant to pay for the running of your account, ask yourself if it is fair that banks are requiring low-earners to subsidise you. If the answer is no, you must surely agree with the OFT that an overhaul of the current account market is long overdue.