Consumers made more than three million complaints about payment protection insurance (PPI) to financial firms last year despite the scandal showing signs of slowing down.
Some 2.48 million complaints about financial products generally were made against firms between July and December last year, marking a 15% drop on the previous six months, according to figures released by the Financial Conduct Authority (FCA).
The latest figures also show that banking-related complaints fell to a seven-year low, although gripes about current accounts have shot up by 8%.
The data adds to evidence that the PPI scandal appears to have peaked, although nearly 3.2 million complaints were received about the insurance over the whole of last year.
Just under 1.4 million PPI complaints were recorded in the second half of 2013, which is a 22% drop on the first half of 2013.
PPI now accounts for a lower proportion of complaints made to financial firms, at just over half (56%), compared with nearly two-thirds (62%) in the first half of 2013.
In 2012, over 4.2 million people made complaints to firms about PPI, which in the past was often added to people's loan or credit card agreements without them realising or wanting it.
Eric Leenders, executive director of retail banking at the British Bankers' Association (BBA), said of the latest figures: "Banks are determined that there will be no repeat of any of the bad practices which caused mis-selling in the past."
The FCA also named Barclays as the most complained about firm, followed by Lloyds Bank, MBNA, Bank of Scotland and NatWest.
Complaints about Barclays have dropped by 17% compared with the first half of 2013, but it still recorded 309,494 fresh complaints in the second half of last year, while Lloyds, sitting in second place, attracted 256,656, showing a 1% increase on the previous six months.
But if the complaints figures for the whole of Lloyds Banking Group are added up, the total comes to a higher figure than those for Barclays, at 493,097. This figure includes Lloyds Bank's sister brands Bank of Scotland, Cheltenham and Gloucester and Halifax.
The figures also show that Barclays attracted the most complaints in the second half of last year about general insurance, including PPI, at 222,946.
In general, the number of complaints about banking products, including current accounts, savings accounts and credit cards, fell by 3% compared with the first half of 2013 to 558,991, which is the lowest six-monthly figure since the second half of 2006.
But within this total, complaints about current accounts jumped by 8% compared with the first half of 2013, with the latest tally reaching 303,110.
The drop in complaints about banking products was driven by a 14% fall in complaints compared with the previous six months about credit cards, an 8% decrease in complaints about loans and a 16% plunge in complaints about savings and other banking products.
Barclays said its PPI-related complaints are down by 24% compared with a year earlier.
It said that looking at the long term trend, nearly 300,000 fewer customers felt the need to complain in 2013 compared to 2010.
Ashok Vaswani, chief executive of Barclays Retail and Business Banking, said: "We recognise that we still have a way to go, even one complaint is one too many.
"We take all complaints seriously and endeavour to make sure that along with finding the immediate resolution, we tackle the root cause of the complaint head on to prevent other customers from being affected.
"Every part of the bank is working to the same goal: to go out of our way to put things right and make our customers' experience seamless."
Lloyds Banking Group said that throughout the second half of 2013, Halifax received just 0.8 banking complaints per 1,000 accounts, Bank of Scotland received 0.9 complaints per 1,000 accounts and Lloyds Bank, which was still joined to TSB for some of the period, received 1.1 complaints per 1,000 accounts.
The group's customer service director, Martin Dodd, said: "Throughout 2013 we have continued to make significant progress on customer complaint handling.
"Our aim remains to reduce the cause of customer complaints in the first place. This year, we'll strive to maintain our position as the bank that receives the fewest complaints, relative to the number of customers, of all major providers."
Financial services firms have a duty to report their complaints figures to the FCA, which publishes them each spring and autumn.
Martin Wheatley, chief executive of the FCA, said the latest figures are an "indication that firms seem to be putting customers at the heart of their business".
He continued: "However, there is clearly more for us all to do to show consumers their interests come first."
Here are the top five most complained-about financial products in the second half of 2013 and the number of complaints made to firms, followed by the percentage change compared with the first half of 2013:
1. Payment protection insurance (PPI), 1,390,756, a 22% decrease
2. Other general insurance products, 321,812, a 3% increase
3. Current accounts, 303,110, an 8% increase
4. Credit cards, 140,829, a 14% decrease
5. Savings, including cash Isas, and other banking products, 82,353, a 16% decrease
Here are the top five complained about firms, in terms of the number of complaints opened in the second half of 2013, according to the FCA, with the number of complaints received in that period and the percentage change compared with the first half of 2013:
1. Barclays Bank, 309,494, a decrease of 17%
2. Lloyds Bank, 256,656, an increase of 1%
3. MBNA Limited, 213,311, a decrease of 10%
4. Bank of Scotland (includes sister brand Halifax), 181,353, a decrease of 18%
5. National Westminster Bank, 175,731, a decrease of 5%