Consumer groups said PPI policy holders considering a complaint should act fast.

BBC: Banks take on FSA over 'illegal' PPI rules

Some claimants never even had a loan, let alone a PPI policy, with the banks who receive demands for compensation, they say.

BBC: PPI: How did the bill ever get so big?

Some people have even complained that a PPI policy was just imposed on them, and premiums deducted, without their knowing anything about it.

BBC: Q&A: PPI claims - how high could they go?

Customers would have to be repaid their PPI premiums, plus interest, if the bank or other firm concluded that the customer would not have bought the policy in the first place if they had been fully aware of the policy's details.

BBC: UK banks lose Payment Protection Insurance challenge