LONDON — A parliamentary committee grilled HSBC executives on Monday about leaked documents showing the bank helped clients evade taxes from 2007 and before.

Margaret Hodge, the chairwoman of the Public Accounts Committee, said that she refused to believe that the executives present were in the dark about what she dubbed “industrial scale” tax avoidance.

“Either you’re completely incompetent in your oversight duties or you knew about it,” she said.

“I don’t believe you didn’t know,” she added.

Those in the line of fire on Monday included Stuart Gulliver, the chief executive, Rona Fairhead, chairwoman of the BBC Trust and the former chairwoman of HSBC’s audit committee until 2010, and Chris Meares, the former head of global private banking.