Also reported in The Mirror, Britain's banks could face another £18billion in PPI payouts after a court granted one couple a significant amount, against regulator rules. Christopher and Joanne Doran have been handed a total of £17,345 by Paragon Personal Finance after a judge said they should be awarded all of the commission they paid plus interest on their loan.

It follows the Plevin ruling last October that stated customers can now claim back commission on transactions, even if they weren't mis-sold PPI.Regulator the FCA said any commissions comprising more than 50% of customers’ premiums were unfair, and ruled that it should be paid back by banks. However, lawyers now argue that customers should have all the commission paid back and not just that over 50%.

The outcome open doors for thousands more claims because it means many more people could be eligible for even bigger payouts that originally estimated. Experts now claim the landmark ruling could add another £18billion to payouts for banks.

"This ruling is hugely significant and sets a new precedent," said Simon Evans, chief executive of the Alliance of Claims Companies.

He said that in total £50billion was paid by consumers to buy policies across the history of PPI selling. Once interest is added, he said, the total figure is £80billion, and that so far the banks had repaid £30billion.

"I've seen a figure of £18billion as the extra amount that could be paid out as a result of this ruling," he added."But that might be too conservative. It could be as high as £30billion."

However in response, the FCA made no reference to the £18billion sum.

"We have always said that different courts could take a different approach. However, it remains our view that our approach has been fair and appropriate," said a spokeswoman.

Christopher and Joanne Doran took Paragon Personal Finance to court on the basis that they weren't told about any commission exchanges at the time of the sale.

The couple approached a credit broker in 2004 for a loan of £30,000, and signed an agreement for the sum of £40,500, made up of a £30,000 loan and a PPI policy with a premium of £10,500. Paragon Personal Finance received commission of £7,985.46, or 76% of the PPI premium, from the insurer.

However, in a landmark ruling, the judge said that the Dorans would not have taken the policy had they known the level of commission. He ordered Paragon Personal Finance to pay the full PPI premium and accrued interest, not just the 26% they would have paid in compliance with FCA rules.

In October last year, the Plevin ruling kicked in that made it possible for more people to claim on the back of PPI. It said that as well as any mis-sold insurance, claims must also factor in any high levels of commission paid by the customer that weren't made transparent at the time of the transaction, plus interest. It means claimants who had their original mis-selling claims turned down can go back to their loan provider and ask to be re-examined.

Under the Plevin rule, if you had PPI on a loan, credit card, mortgage or any other form of debt, and the commission was over 50% (without your knowledge), you can now claim the amount over 50% back. However in the case of Christopher and Joanne Doran, the judge ruled they were entitled to the entirety of the commission paid - which was 76% of the premium, plus interest. In doing so he rejected the FCA’s guidance, leading claims management firms to claim others will be entitled to new, higher payouts. The problem, however, is that to claim back the full amount, you will have to go to court.

To date, around 1.2 million complaints have proved successful under the Plevin rule, out of the total of 13 million PPI pay-outs. In total, banks and insurance companies have had to pay out a total of £30billion to compensate customers. Lloyds Bank has paid out £18.8billion for mis-selling claims, while Barclays has paid more than £9billion and RBS nearly £5billion.

Consumers now have until 29 August 2019 to make claims for PPI before the FCA's final deadline kicks in. On average, it takes six months for a claim to complete - with the regulator urging people to apply now, to avoid the last minute rush.