Fees and charges triggered by mis-sold PPI premiums should be paid back, the Financial Ombudsman Service said after a BBC investigation claimed customers could have possibly been under-compensated by £1 billion.
Principal Ombudsman Caroline Wayman said: "If a fee is the result of the mis-sold PPI it should be given back, and if it's not included that would be a mistake."
She also recommended that credit card customers who fear their fees and charges were left out of compensation calculations approach their banks to discover what happened.
More top news
Tony Davies was the first civilian to reach Pc Palmer after he was stabbed during the Westminster attack.
Defiant Londoners put on a show of solidarity for the victims of the Westminster terror attack at a vigil in their honour.
Weather set to improve with plenty of sunshine by Saturday