What's the point of an audit if it fails to detect when a company's about to go under? The sudden collapse of BHS, Carillion and Patisserie Valerie has dented public confidence in the firms that audited them and prompted calls for a shake-up of the audit industry. Would more competition in the sector, which is dominated by four big players, drive audit quality up? Do accountants need to be more robust in challenging company figures?

Joining Evan Davis for The Bottom Line:

Bill Michael, UK Chairman and Senior Partner at KPMG.Jac Berry, Audit Partner and UK Head of Quality at Mazarsand Christopher Humphrey, Professor of Accounting at the Alliance Manchester Business School