The chair of the U.K. parliament's Public Accounts Committee says the former chief of HSBC must face serious questions after once-secret papers outlined how the bank helped the wealthy dodge taxes.

Margaret Hodge told the BBC on Monday that Stephen Green, HSBC's former CEO, was either "asleep at the wheel, or he did know and he was therefore involved in dodgy tax practices."

Hodge's comments came after details of some 30,000 accounts with 78 billion pounds of assets ($120 billion) were analyzed by the French daily Le Monde, The Guardian in Britain, the BBC and the Washington-based Consortium of Investigative Journalists.

The bank says in a statement that "these disclosures about historical business practices are a reminder that the old business model of Swiss private banking is no longer acceptable."