Which? and MoneySavingExpert.com have also launched a campaign to highlight how easy it is for consumers to claim back payment protection insurance without using a claim management company.

CMCs have been particularly prolific with television, email and text messaging adverts in light of last year’s PPI mis-selling ruling.

However, many consumers are unaware that CMCs often take large fees from successful cases.

In a survey of 2,000 people, 49 per cent did not know using a CMC company was no more successful than making a claim themselves and 25 per cent did not know CMCs often took a 25 per cent plus VAT fee.

Over half of consumers who had used a CMC previously would not use one again, some 37 per cent said this was due to poor value for money.

Which? consumer group and MoneySavingExpert want people to know how easy it is to claim themselves.

Which? executive director Richard Lloyd said: “This new research shows that many people don’t realise there are simple, easy to follow steps to reclaim their money for free and so they’re turning to CMCs, too often unaware they charge a fee.”

Martin Lewis, from MoneySavingExpert.com, said: “If people make a rational decision to give a huge 30 per cent of what they’re due to a claims handling company in full knowledge they could do it themselves- I’ve no problem. Yet sadly very few are in that position. Many are persuaded under false pretences and the dire lack of regulation means it’s tough to tell legit firms from the rest.”