Major banks are making changes to their basic accounts that could push more consumers out of the banking system, a consumer champion has said.
Consumer Focus made the warning as Barclays altered its basic bank account.
This will see a tripling in the maximum daily charge for missed direct debit payments if there are insufficient funds to cover the payment.
A customer could be charged up to £24 instead of the current £8 if three missed payments occur in a day.
Consumer Focus said all the evidence showed the risk of such charges, even if the likelihood was remote of incurring the maximum amount, stopped many people from opening a bank account.
The changes come on top of amendments RBS made last month which mean its basic bank account customers can only withdraw cash at RBS group's cashpoints and not those of other banks.
The watchdog said it feared the moves heralded a downward trend in "accessibility and penalties on basic banking which could discourage the poorest and most vulnerable customers from using bank accounts".
Oliver Morgans, financial services expert at Consumer Focus, said: "These changes to basic bank accounts are a backward step by banks which could increase financial exclusion.
"Living without a bank account can make it hard to live in the 21st century and can create financial penalties for the households who can least afford it.
"The Government already faces an uphill struggle to persuade customers to sign-up to a bank account when many people distrust banks and the charges they make. These changes will make that hill even harder to climb."
