A decade after he took office and ended 11 years of Coalition rule, former prime minister Kevin Rudd has launched a full-throttle attack on the global power of Rupert Murdoch’s News Corporation, which backed his rise.

Accusing other media of being too frightened of retribution to air his arguments, Rudd has labelled News Corp a “cancer” on democracy and called for a royal commission into its relationship with the federal Coalition.

“They go after people who have the audacity to raise a question about their behaviour,” Rudd told The Saturday Paper.

“… It’s one of the reasons I’m speaking out directly, so that people can have a normal national conversation rather than a continued national embarrassed silence about this.”

Rudd accuses the media conglomerate of persistently working for the election of Coalition governments and against Labor in Australia, insisting it only endorsed his own elevation into government almost 10 years ago when it became clear that’s how Australians planned to vote.

“What Murdoch has done through the concentration of media power in Australia and the ‘Foxisation’ of Sky News in Australia is to create an echo chamber for far-right politics.”

He believes the relationship between the current Coalition government and News Corp should face official scrutiny in the way he says Labor governments have over the past four decades.

“The Liberal Party has seen fit to call a series of opportunistic royal commissions into the Labor Party over many decades now,” Rudd says. “They did it against me, they did it against Gillard, they’ve done it against Shorten. They did it against previous Labor governments going back to Gough Whitlam.”

One specific focus of Rudd’s criticism is the handling of the national broadband network (NBN). He alleges a cosy relationship between the federal Coalition and News Corp has led to a substandard NBN compared with the version his government proposed a decade ago.

“Why this matter has not been the subject of more comprehensive debate and inquiry, I do not know,” Rudd says.

“If ever there was a case for a royal commission in Australia on the waste of public funds and the unseemly relationship between the Liberal Party on the one hand and the Murdoch party on the other in the destruction of the NBN model for Australia, this is it.”

The Abbott and Turnbull governments dismissed Labor’s fibre-to-the-home broadband proposal as too ambitious and too costly, modifying it to fibre-to-the-node – usually a neighbourhood hub – and using a mixture of existing copper wire and pay TV cabling for the final connection to the home, or customised individual fibre links, for which consumers pay extra.

Rudd rejects the Coalition’s arguments and alleges it was News Corp’s opposition to the plan that led to its modification – because it could otherwise boost competitors to its Foxtel pay television network, including Netflix, which relies on fast broadband connection.

“People need to look very carefully at why they’ve ended up with such a dog of an NBN in Australia, which is a laughing stock of the developed world, whereas when we launched it, we were in a position to lead the world. This is a genuine national disgrace, scandal and tragedy.”

However, Communications Minister Mitch Fifield rejected Rudd’s allegations. “Kevin Rudd is living in a bizarro world,” he told The Saturday Paper. “The only thing he can reflect on is a failed project. The Turnbull government has turned it around and is delivering the NBN to millions of homes and businesses across the country at $30 billion less cost and six to eight years sooner than Labor. Thanks to our policy, all Australian homes and businesses will have fast broadband by 2020.”

NBN Co released its latest quarterly results this week, with chief executive Bill Morrow insisting it would iron out any problems with the broadband rollout within the next nine months.

“We are delivering a network at an unprecedented pace,” Morrow said. “We are overcoming obstacles almost on a constant basis in terms of being able to get to every home in this country.”

But Rudd’s attack on the Murdoch media empire extends beyond the NBN and beyond the media giant’s role in Australia.

He also criticises its influence on politics in the United States and Britain, holding it largely responsible for the election of Donald Trump as US president and the success of the Brexit campaign for Britain to leave the European Union.

“If it was not for the Murdoch press through The Sun newspaper in Britain campaigning so viciously in support of Brexit, it’s an open question whether Brexit would have happened,” Rudd says.

“It’s Fox News in America that has in large part made the Trump phenomenon possible and sustains the Trump phenomenon at present. It is the single friendly outlet for this president and acts as a national echo chamber for that huge slice of Americans who are open to conservative views but have none of those conservative views ever challenged but only reinforced with one level of prejudice after another. If you want that for Australia’s television future, well you’re welcome to it.”

Rudd declined to offer a view on the takeover of the Ten Network by US network CBS, which was finalised this week, heading off a bid led by News Corp’s Lachlan Murdoch.

But he argues that Murdoch’s existing broadcasting arm, Sky News, has shifted away from “straight up and down reporting the facts” to being a vehicle for right-wing views.

“What Murdoch has done through the concentration of media power in Australia – where he owns 70 per cent of the print media and seeks to expand that in television further – and the ‘Foxisation’ of Sky News in Australia – is what he’s already done in the United Kingdom and what he’s done in the United States, which is to create an echo chamber for far-right politics,” Rudd says.

He says media concentration is one of the reasons he fears for the future of democracy as a system of government. In his new memoir, Not for the Faint-hearted, Rudd describes the democracy model as “fragile”.

He now suggests the direct influence of Rupert Murdoch poses part of that risk, arguing that the “global honeymoon with liberal democracy may well be waning” and that Russia and China are taking advantage of that.

“We have a responsibility in the collective West to demonstrate that the democratic… the liberal democratic project resting on open markets, open societies, open economies and open politics, is sustainable for the future,” he says. “Because if we can’t establish for ourselves that it can work, how on earth will it have continued appeal for countries that seek to emerge from poverty in the first place?”

Rudd says democracy “lives and breathes on the basis of a free press”.

“Yet what we have in Australia is a highly concentrated press in the hands of an individual who has a global reputation of supporting far-right causes, union-bashing, union-smashing.”

While Australian media, including from the News Corp stable, have published and broadcast scathing criticisms of Rudd – some from his own colleagues – for abandoning his plan to tackle climate change during his first term in office, the former prime minister accuses Rupert Murdoch of campaigning consistently against action on climate change and also against “corporate tax responsibility”.

He says News Corp’s aggressive prosecution of those views helped create “a real culture of fear” among institutions and leaders of “the bully-boy culture of Murdoch Incorporated”.

Speaking from Britain, where he has begun a doctorate examining the world view of China’s president Xi Jinping, the former prime minister says he is not suggesting News Corp alone is responsible for destabilising democracy.

He cites other “corroding forces” including the failure of centre-right and centre-left governments to address community challenges such as technological change, the stresses on employment and loss of identity.

“It’s wrong to pin the current crisis of Western democracies to a single factor,” he says. “There are multiple factors at play: the inroads of globalisation; the inability of mainstream politics to deal with essential challenges, which are causing people to fall off the bus completely; as well as an utterly compromised mainstream media by the presence, the dominant presence in the marketplace, of the Murdoch media empire.”

Despite this criticism, Rudd acknowledges that he met with Rupert Murdoch ahead of the 2007 election to try to secure his support.

“To me it was simple,” he writes in his memoir. “If I wanted to win the 2007 election from the Liberals, the first such win in 24 years, I had to reduce as much as possible the level of media hostility towards the Labor Party.”

He said he gave no undertakings and none were sought. He observed: “Our cordial relationship would not last all that long.”

Rudd did forge a close relationship with Chris Mitchell, the then editor of Murdoch’s flagship local publication, The Australian. But that relationship has deteriorated with the publication of Mitchell’s own controversial memoir, Making Headlines, last year.

Mitchell declares he became too close to Rudd and says he acted on Rudd’s suggestion – made in a phone call from the Great Wall of China – to commission the Newspoll that found a Rudd–Gillard Labor leadership team had a better chance of winning the 2007 election than incumbents Kim Beazley and Jenny Macklin. A leadership change followed.

Responding to questions about Rudd’s broad criticisms and his call for a royal commission, a spokeswoman for News Corp told The Saturday Paper: “Mr Rudd is entitled to his opinions. It is a role of the media to scrutinise governments, it is what defines a democracy, and we stand by our role in doing that.”

Prime Minister Malcolm Turnbull was asked for his assessment of the state of democracy during a swing through Asia this week for the annual APEC and East Asia summits.

“I prefer democracy with Australian characteristics rather than socialism with Chinese characteristics,” Turnbull responded.

He rejected suggestions democracy was under threat, choosing to respond in the context of the cut and thrust of Australia’s parliament.

“No. I know that would make a good headline, but I think, truthfully, everyone looks at parliamentary events at any given time and says, ‘Gosh, it’s unruly.’ And you know what? It has always been so. Democracy is like that. It is often noisy and people disagree.”