NEVER has a single tweet caused such consternation among the British commentariat.

“The main thing I’ve learned from working in the British media is that much of it is a cult. Afflicted by a suffocating groupthink, intolerant of critics, hounds internal dissenters, full of people who made it because of connections and/or personal background rather than merit,” Guardian columnist Owen Jones tweeted last month.

The indignant responses — perfectly illustrating Jones’s argument — came thick and fast.

“No-one tells me what to think,” replied Deborah Haynes, the defence editor at The Times.

“Nobody tells me what to think or write,” parroted political commentator and Time Person of the Year in 2007 Jane Merrick — a point repeated again by Sebastian Payne, political leader writer at the Financial Times. “Balls Owen,” was David “WMD” Aaronovitch’s considered take.

There is a long history of journalists making this arrogant and self-deceiving assertion about their own independence. “The most stupid boast in the history of present-day journalism is that of the writer who says: ‘I have never been given orders; I am free to do as I like’,” noted the muckraking US foreign correspondent George Seldes in the 1930s.

Speaking in 1993, US writer Michael Parenti said his response to journalists who make this “stupid boast” is: “You say what you like, because they like what you say.”

He continued: “You don’t know you’re wearing a leash if you sit by the peg all day. It’s only if you then begin to wander to a prohibited perimeter that you feel the tug, you see. So you’re free because your ideological perspective is congruent with that of your boss.”

Largely ignored by the mainstream media, there are journalists who have spoken honestly and critically about the limits of the supposedly free and critical Western media.

For example, Matt Kennard was a reporter with the Financial Times for over four years, reporting from four continents before he left to write his exposé of the global elite, The Racket: A Rogue Reporter vs The Masters of the Universe.

“The default position in our media — which is what they call ‘unbiased’ — is to support corporate power and US militarism,” Kennard argued at the launch of his book in Waterstones in 2015.

“If you do that you are unbiased. If you deviate from that you are a leftist, you are a radical, you are a maverick.”

Kennard recently gave a good example of the ideological straitjacket worn by most mainstream media journalists.

“You learn by accretion (and subconsciously) what can and cannot be said,” he tweeted. “So you learn you can say ‘Russian expansionism’ but you can't say ‘US imperialism.’ You can say ‘Russia-backed Assad regime’ but you can't say ‘US-backed Saudi regime.’ It's insidious.”

After working for 15 years as a foreign correspondent for The New York Times, Chris Hedges has become a strong voice for radical progressive change.

He is also highly critical of the corporate media, which, in a 2014 piece entitled The Myth of the Free Press, he argues “plays an essential role in the dissemination of official propaganda.”

“Those reporters who care … about truth will eventually become management problems,” Hedges explained in the 2016 documentary film All Governments Lie: Truth, Deception and the Spirit of IF Stone.

“And the ones who can read power, in essence function as courtiers, know how to play the game, the veneer of objectivity, neutrality, impartiality, truth, and yet assiduously serve, in essence, power, are the ones who rise within the institution.”

I personally encountered the limits of our so-called free press writing for a progressive column published in the Eastern Daily Press regional newspaper in the mid-2000s.

In 2004 I submitted an article that summarised some of the human rights abuses perpetrated by British armed forces in recent history, ending with the death of the Iraqi Baha Mousa in British custody in 2003.

The paper refused to publish this column. The news editor told me it had been rejected for two reasons: first, the column was too contentious, and second they felt it was not appropriate to publish the column in a week when two British soldiers had died in Iraq.

The academic evidence highlighting the media’s pro-Establishment bias — also largely ignored by the mainstream media, unsurprisingly — broadly echoes these individual experiences.

In his new book Media, Propaganda and the Politics of Intervention, Dr Florian Zollmann, a lecturer in journalism at Newcastle University, notes: “The news media in liberal democracies operates as a propaganda system on behalf of state-corporate elite interests.”

Conducting a detailed content analysis of elite Western press coverage of human rights abuses in recent conflicts, Zollmann finds: “If countries designated to be ‘enemy’ states of the West conduct human rights violations, the news media highlights these abuses and conveys demands for action to stop human rights abuses.”

However, if “Western states or their ‘allies’ are the perpetrators of human rights violations the news media employs significantly less investigatory zeal in its reporting and virtually no measures to stop abuses are conveyed.”

Writing in the book’s foreword, Professor Richard Keeble highlights the hypocrisy of the Western media: “There is no hysterical, sustained, highly personalised demonisation of the leaders of Saudi Arabia — as applied in the past to dictators” including Saddam Hussein, Colonel Gadaffi and Slobodan Milosevic.

Turning to domestic politics, Dr Mike Berry, a Lecturer at Cardiff University’s School of Journalism, Media and Cultural Studies, conducted a study of the BBC Today programme coverage of the financial crisis, focusing on the two weeks around the bank bailouts.

The results? “Opinion was almost completely dominated by stockbrokers, investment bankers, hedge fund managers and other City voices,” he noted in a 2013 article for The Conversation.

“Civil society voices or commentators who questioned the benefits of having such a large finance sector were almost completely absent from coverage.”

“The evidence from the research is clear,” Berry concludes. “The BBC tends to reproduce a Conservative … pro-business version of the world.”

Berry’s conclusions about the BBC Today programme can be applied more broadly to the wider British media, it seems.

Summarising his new co-edited book The Media and Austerity, Steve Schifferes, professor of financial journalism at City, University of London, noted in another article for The Conversation that “the UK financial press was much slower to criticise the austerity policies of the government than in other parts of Europe.”

This meant austerity has “become accepted as the only way to tackle the legacy of the global financial crisis of 2007-08, despite many economists arguing it would further damage the economy.”

Reaffirming Berry’s findings about the BBC, Schifferes notes when the press “consulted economists at all” it “quoted City economists for comment on short-term news events, rather than seeking out a deeper understanding of government policy.”

Pushing back against this media-driven consensus on Western foreign policy and austerity is Jeremy Corbyn’s Labour Party.

However, because of the very real challenge to the status quo that Corbynism represents, the media have savagely and repeatedly attacked the Labour leader and his allies.

Corbyn “was represented unfairly by the British press through a process of vilification that went well beyond the normal limits of fair debate and disagreement in a democracy,” a 2016 London School of Economics study found after analysing the first few months of his leadership.

“The British press has repeatedly associated Corbyn with terrorism and positioned him as a friend of the enemies of the UK,” the report’s summary explains.

“The overall conclusion from this is that in this case UK journalism played an attack dog, rather than a watchdog.”

It is not all bad news. The ongoing work of non-corporate organisations such as Media Lens, Novara Media, Open Democracy, Peace News and the Morning Star, along with writers such as Dr Tom Mills, author of the essential The BBC: Myth of a Public Service, have contributed to a growing awareness of the propagandistic nature of the British media.

Will mainstream journalists join them in thinking critically about the ideological limitations and groupthink of the Fourth Estate? Don’t hold your breath.

Follow Ian Sinclair on Twitter @IanJSinclair.