PwC has been fined £5.1m and "severely reprimanded" by the Financial Reporting Council for "extensive" misconduct in relation to its auditing of now-defunct professional services firm RSM Tenon.

It is the largest-ever penalty issued by the accounting watchdog, according to the FRC. The previous record was a £5m fine — also against PwC and issued in May, in relation to the 2010 collapse of social housing provider Connaught.