You’re unlikely to hear a PR agent publically criticise a major news outlet, unless they’re feeling commercially suicidal that day, yet sensationally Matthew Freud has made a gloves-off attack on Fox News, the leading US TV news network owned – and this is where it gets even more surprising – by his father-in-law, Rupert Murdoch.

Agreeing to contribute his thoughts to a New York Times profile of Fox founder and boss Roger Ailes, Freud said: “I am by no means alone within the family or the company in being ashamed and sickened by Roger Ailes’s horrendous and sustained disregard of the journalistic standards that News Corporation, its founder and every other global media business aspires to.”

Commentators suspect that his comments don’t so much represent a spectacular gaffe by Freud as a tactical move to destabilise the station chief. Michael Wolff, a biographer of Murdoch said “Matthew Freud, a PR man of extraordinary craftiness, is not going to say anything off the cuff, certainly not that.”

Fox founder and boss, Roger Ailes is known to have had a tempestuous relationship with Murdoch whose family is said to be more left leaning than arch-republican Ailes, a former aide to President Nixon who told the New York Times that he “built this channel from my life experience” and not out of the mould of a liberal media elite.