Thousands of bank customers due payments compensation
Up to 30,000 consumers may be eligible for compensation, after some banks failed to cancel regular payments from their accounts.
The Financial Conduct Authority (FCA) said some banks have not been stopping such payments when asked to do so.
The payments concerned are known as Continuous Payment Authorities (CPAs), or recurring transactions.
Those with payday loans and gym membership are amongst those affected.
Since 2009 banks and building societies have been obliged to cancel CPAs when asked to do so by their customers.
But the FCA said that, up to now, some banks and mutual societies have not been doing what they were asked, forcing customers to cancel the payments with the businesses themselves.
However, the banks have now promised to stop the payments when customers tell them to.
"Today customers can be confident that when they ask for a Continuous Payment Authority to be cancelled - it will be cancelled - and that it can be done easily," said Clive Adamson, the FCA's director of supervision.
In the meantime the largest lenders have agreed to review each complaint they have received on the issue, and to pay compensation where necessary.
Payments worth more than £7.5bn a year are made through CPAs.
On average each transaction is worth £45, with those on payday loans paying £80.
Those affected can phone the FCA helpline, which is free, on 0800 111 6768.