Data from the Financial Services Authority found that complaints to the FSA had increased by three per cent overall.

In total the FSA received 251,563 complaints about Barclays, the highest number for a single insituution.

Over half of these cases were upheld in the customers’ favour. The biggest Barclays sector was the banking branch which received 162,611 complaints.

Lloyds received 181,907 complaints, Santander received 168,888 and Natwest received 147,109.

However the number of banking specific complaints were at their lowest level overall since 2008 with 812,197 complaints.

This was 22 per cent less than in 2010.

The FSA said: “The FSA is committed to greater transparency where it will benefit customers. Publishing this data brings complaints to the attention of firms and consumers alike and gives firms a benchmark and an incentive to improve how they treat their customers and handle complaints.”

A key reason for the high number of complaints was the ongoing PPI complaints. The volume of these complaints also meant that total number of complaints closed within eight weeks fell from 84 per cent to 72 per cent.

Adam Phillips, chair of the Financial Services Consumer Panel, said: “Consumers have the right to know about poor firm performance, such as the nature of complaints and a firm’s record in handling performance.

“It is not surprising that consumers’ satisfaction with the financial services industry is so low when the industry uses the risk of a loss of confidence in firms to withhold information that would be regarded as essential in other sectors.”