New figures from the Financial Services Authority (FSA) - a non-governmental body granted statutory powers by the Financial Services and Markets Act 2000 - have revealed an increasing level of refunds across the first half of 2011.
As many as 16 firms, which accounted for 92 per cent of PPI complaints, paid back Â£29 million in January, followed by similar levels in the following months.
However, in May this sum rose to Â£37 million, before climbing to Â£65 million in June.
Margaret Cole from the FSA described the handling of PPI complainants as an "indelible stain" on the record of the financial industry.
Which? executive director Richard Lloyd said the refund total may sound like a lot "but when you compare it to the Â£7.4 billion that the banks have set aside to cover PPI mis-selling, you can see that this is just the start".
By Asim Shah