Earlier this year, the Financial Reporting Council, which oversees the activities of the AADB, said it would take legal advice relating to how its disciplinary arm would continue to function, in the event of large cost awards made against it.

The FRC took legal advice following the then Accountancy Investigation and Discipline Board's major defeat at its first tribunal - a case involving bus manufacturer Mayflower and its auditors PricewaterhouseCoopers - which saw a £987,000 cost award made against it by an independent tribunal.

The tribunal dismissed complaints against Mayflower's finance director David Donnelly and PwC and ordered the FRC to pay £400,000 towards PwC's costs and £587,500 towards Donnelly's costs.

At the time, FRC chief executive Paul Boyle said the regulator was less likely to bring complaints if the rules remained as they are.