Wiltshire mechanic Richard Cullen, 65, had 22 credit cards with debt, four of which were issued by the Bank of Scotland who were owed £35,000.
Seymour Fortescue, chief executive of regulators the Banking Code Standards Board, said he found the claim “extraordinary” but added: “I will investigate to see if there has been a breach of the banking code.”
His comments on BBC News come ahead of a Panorama investigation into debt as the governor of the Bank of England and other leading figures call for action over rising debt levels.
Bank of Scotland told the investigators that despite raising Mr Cullen’s credit limit from £1,000 to £7,700 on one of his cards, the bank felt it had not made mistakes.
Mr Cullen’s widow told the same report that her late husband had some responsibility for his debt, but also stated that “surely the bank must take responsibility as well for allowing him to go on and on getting deeper and deeper into debt”.