Barclays has topped the list of the most complained-about bank, although the number of reported grievances against financial services companies has fallen by 15 per cent overall.
The Financial Conduct Authority (FCA) said that almost 310,000 new complaints from retail customers had been opened against Barclays from July to December last year.
That marked a fall of 17 per cent from the first half of the year, but was still around 50,000 more than second-ranked Lloyds.
However, Lloyds was the only financial services company to see complaints edge a fraction higher.
Credit card issuer MBNA, Lloyds-owned Bank of Scotland and National Westminster Bank, owned by part-privatised Royal Bank of Scotland, took the last three slots in the table.
“No firm wants to top this particular list, and they all should be striving to ensure that customers are being treated fairly and not given cause to complain,” said FCA chief executive Martin Wheatley, releasing the latest complaints data.
“This is an indication that firms seem to be putting customers at the heart of their business. However, there is clearly more for us all to do to show consumers their interests come first.”
The majority of customer complaints still centre on payment protection insurance, for which banks have set aside more than £20bn for compensation claims, followed by gripes about other insurance products, current accounts, credit cards and savings.