More than £21bn of the UK’s credit card debt is covered by unenforceable credit agreements and could be written off, according to financial claims management company Cartel Client Review.??

Cartel has based its projection partly on an estimate from money education charity CreditAction that total credit card debt in the UK now stands at around £53bn.

Cartel added that 40 per cent of all financial products brought to them for review can be claimed against.??The claims management firm said that an average client has 10 financial products, of which four can be claimed against.

Carl Wright, managing director for Cartel Client Review, said: "Previous estimates around the amount of unenforceable credit agreements put the figure at 25 per cent, but this does not tally with our observations. On average, I’d say our customers can claim against as much as 40 per cent of their credit agreements.

"??He added: "There are specific rules that lenders must adhere to when they sell a financial product to a consumer. If these have been breached, lenders should admit their mistakes and stop dragging their heels through the legal system. This only results in unnecessary additional legal costs for all involved.

"??Figures from CreditAction also show that the UK collective credit limit on credit cards is £158bn, which is an average credit card limit of £5,129 per person. The charity said the average interest rate on credit card lending is currently 17.6 per cent - 17.1 per cent above base rate (0.5 per cent).

The Bank of England announced earlier this month, however, that personal borrowing fell by £600m in July, taking the total owed by individuals down to £1.457 trillion.