Its survey found more than a quarter of bank customers – around 12m – had problems with their current account in the last year and the problem was not satisfactorily dealt with in more than one in five cases.
Lloyds topped the list, with 30 per cent reporting a problem, while 29 per cent of Co-operative and Bank of Scotland customers had gripes. Some 28 per cent of RBS customers reported problems.
Two-thirds of those with a problem made a complaint, according to the survey, but, of those, three out of ten had to raise the matter more than once. Many that did not complain cited expensive phone calls as a deterrent.
In another report out today, the Institute of Customer Service rated customer service in various sectors, based on a poll of 26,000.
The banking sector was rated eighth out of 13 for customer satisfaction. But there were plaudits for First Direct and the Co-operative Bank, who were ranked third and eighth overall among firms for customer service.