Former justice minister Frances Fitzgerald was shown an email and a print-out outlining a challenge by legal representatives of Garda Commissioner Noirin O'Sullivan to the credibility of garda whistleblower Sgt Maurice McCabe, the Charleton tribunal has heard.

Backroom ministerial media advisers are taking home salaries worth more than €3m a year, despite concerns over the stability of the Government and the limited amount of legislation passed since the general election.