Complaints about the payment protection insurance scandal have fallen for the first time in three years, figures from the City regulator have shown.
Just under 1.8 million new PPI cases were opened in the first half 2013, marking a drop of almost one fifth (18%) from an industry peak of 2.2 million complaints received in the previous six months, Financial Conduct Authority (FCA) figures showed.
PPI is said to be the biggest financial mis-selling scandal this country has seen, with more than £18 billion having been put aside by banks to compensate customers who were sold insurance they did not want or need, amounting to around double the cost of the Olympic Games.
Until now, complaints made to financial firms about PPI had been steadily rising each half-year since around 2010.
The FCA's findings also show that 1.3 million customer complaints about financial services generally were generated by just five firms - Barclays; Lloyds TSB which has recently split into two separate banks; MBNA; Bank of Scotland (which also includes the brand Halifax); and Santander.
Barclays was named by the FCA as the most complained about firm and the bank also topped the table for receiving the most PPI-related complaints.
Overall, half a million fewer consumer complaints were made to financial services firms in the first half of this year compared with the last six months of 2012, with a total of 2.9 million gripes recorded between January and June.
Nine out 10 (92%) of complaints made to financial services firms were dealt with within eight weeks, marking the highest proportion seen since records began seven years ago.
Complaints about current accounts also dropped on the previous half-year, with just over 280,000 grievances recorded. New industry rules were recently introduced which make it easier for people to ditch their current account provider and switch to another bank.
Credit card complaints saw a sharp two-thirds drop compared with the previous half-year, with just over 164,000 new complaints recorded in 2013. Complaints about savings, including cash Isas, also edged down by 3% on the last six months, with just under 98,000 new grievances.
A total of 370,733 complaints were recorded by Barclays, meaning it continues to be the most complained about financial firm, despite seeing an 11% fall in complaints on the previous half-year.
Ashok Vaswani, chief executive of Barclays Retail and Business Banking, said: "Whilst the number of complaints we receive is reducing sustainably as we work hard to put our customers at the heart of everything we do, this is no time for self-congratulation.
"Even one unhappy customer is one too many which is why we must always strive to learn lessons on how we can do better."
Lloyds TSB was the second most complained about firm, with 253,735 complaints opened in 2013 so far. TSB recently split from Lloyds and the pair have re-branded as standalone names.
If their complaints are added to those of Bank of Scotland/Halifax, which are in the same banking group, this would make nearly half a million complaints (475,984), putting Lloyds as a group ahead of Barclays' complaints figure.
Lloyds Banking Group said that its brands receive fewer than one banking complaint for every 1,000 customer accounts.
The group's customer service director Martin Dodd said "significant improvements" have been made, adding: " In order to draw accurate comparisons between providers it is important to look at banking complaints figures in the context of the number of accounts."
Richard Lloyd, executive director of consumer group Which? said complaints figures are still too high.
He said: " We want banks to deal with complaints swiftly and fairly and to explain what steps they are taking to stop the same problems occurring in the future."
The FCA's figures also showed there were £2.4 billion of PPI compensation payouts made in the first half of the year, making up 94% of all redress payments.
Some £54 million was paid back to customers who complained about investment products while there were £52 million of payments for banking products, including current accounts, credit cards and savings.
The total £2.55 billion redress bill in the first half of this year was smaller than the £2.96 billion of payouts made in the previous six months.
Banks are also upholding more complaints in consumers' favour. Just over half (51%) of complaints reported in 2013 so far were upheld, marking an increase from 46% in the previous six months.
The FCA said an increase in the number of PPI complaints being upheld was the "main cause" of the overall increase, with 53% of PPI and general insurance complaints being upheld, up from 48% in the last six months of 2012.
Financial firms have a duty to report the customer complaints they receive to the FCA, which publishes the collective figures every six months
Martin Wheatley, the FCA's chief executive, said: "We expect firms to put customers at the heart of their business - an important part of this is the way they handle customer complaints ."
A spokesman for the British Bankers' Association (BBA) said the figures are "encouraging".
He said: " Banks continue to improve their products and services, and have placed their customers at the centre of everything they do.
"Banks are determined that there will be no repeat of any of the bad practices which caused previous mis-selling in the past and have overhauled incentive structures. Staff are now rewarded for high levels of customer service and not sales volumes ."