The number of PPI complaints has soared to 2,000 a day, more than doubling in the second half of 2012, and making up nearly three quarters of all financial complaints.
New figures from the Financial Ombudsman Service (FOS) released today show the number of PPI claims rose from 85,562 in the first half of 2012, to 211,885 in the second.
Taking into account all complaints, including mortgage and investment issues, the FOS dealt with a record number between July and December last year, handling 283,251, a 110% increase on the previous six months.
The fresh figures take the total number of mis-sold PPI complaints to more than 600,000, with no end in sight. The FOS said five financial service groups accounted for 78% of all new PPI cases, with Lloyds TSB at the top of the table with more than 42,000 new complaints.
Unprecedented levels of complaints
Natalie Ceeney, chief ombudsman, said the service is dealing with unprecedented levels of complaints.
"Over the last year or so, we have geared up substantially to deal with these record complaint numbers and we are now resolving more cases each week than ever before," she said.
"However, as the complaint levels show no sign of slowing, customers are increasingly having to wait longer to get their complaints sorted - with many business still continuing to cause unnecessary delays."
The FOS said some businesses had 97% of complaints upheld against them, while some had only 6%.
Richard Lloyd, executive director at consumer rights group Which?, described the figures as "shocking".
"Some banks are clearly not making it as straightforward as they should for people to get the money back they're legitimately owed," he said.
"[Banks] should be proactively contacting past PPI customers so people are aware they can claim without using unnecessary and expensive claims management companies."
Matthew Parden, managing director of Duncan Lawrie Private Bank, said: "Until banks focus on customer care and building a credible relationship with individuals, they can expect more of the same.
"Despite this, many high street banks continue to enjoy seemingly undeserved customer loyalty."