Barclays is threatened with multi-million pound fines and its boss Jes Staley will suffer a significant pay cut after he broke rules to protect whistleblowers in an effort to defend a friend against “malicious smears”.

The Financial Conduct Authority (FCA) and the Bank of England’s Prudential Regulation Authority (PRA) have launched investigations into both Barclays and Mr Staley after it emerged he twice tried to identify the author of two anonymous letters sent last June that raised concerns about a senior banker that Mr Staley recently recruited.