
Of a record total of 69,841 complaints about the industry, Lloyds, Barclays, RBS, Abbey and HSBC all received more than 3,000, accounting for 38,286 cases.
Credit cards, loans and current accounts were the most complained about, while insurance and payment protection products also came under attack.
The news comes at a time when trust in the nation's financial institutions is already at an all-time low.