In the other, more Thatcherite, corner, there’s Rupert Murdoch; the Antipodean megalomaniac, a self-styled champion of the underdog, a billionaire airing grudges about all that is repugnant about class-ridden Britain. For Private Eye’s pox on both their houses, Murdoch is the ‘Dirty Digger’.

Murdoch, so Westminster wisdom goes, hates Cameron — and never really rated him much anyway, having been talked into backing his run at Downing Street by his News International confidantes, Cameron’s fair-weather Oxfordshire friends, long before the world ever heard much about the blight of phone hacking.

But as the hacking disgrace and its unfolding scandals have consumed nearly all in their wake this past year, Murdoch detests the Cameronian establishment elite who once courted him for allowing this very public, elongated humiliation of his life’s work to happen at all, just as he — or was it they? — was poised to deliver his biggest ever deal, the $12 billion acquisition of all of BSkyB he thought was sewn up.

“It’s starting to seem a little like an embrace to the death,” Charlie Beckett, director of the London School of Economics’s POLIS journalism think tank told The Global Mail.

The latest episode of this compelling danse de la mort came yesterday, May 1, in what was the most humiliating public denunciation of Murdoch in his 60-year business career.

“Rupert Murdoch is not a fit person to exercise the stewardship of a major international company,” concluded the House of Commons’ Culture, Media and Sport Committee of British parliamentarians.

“On the basis of the facts and evidence before the committee, we conclude that if at all relevant times Rupert Murdoch did not take steps to become fully informed about phone hacking, he turned a blind eye and exhibited wilful blindness to what was going on in his companies and publications.

“This culture, we consider, permeated from the top throughout the organisation and speaks volumes about the lack of effective corporate governance at News Corporation and News International.”

The Commons report was brutal. But in the partisan party division of the committee over its most damning language condemning Murdoch and News Corp, did David Cameron blink and wave a white flag at the Murdochs? Do the four Tories publicly breaking with their Labour and Liberal Democrat committee colleagues suggest Cameron was telegraphing a truce message to Rupert?

There’s much to indicate that Murdoch is out for payback on Cameron and his kind: Rupert’s mischievous support for independence-minded Scots seeking to break Britain up in what would be the ultimate payback; his casual and damning evidence to the Leveson Inquiry last week about how Cameron swanned about the Greek Islands on Murdoch family yachts, flown there on the family’s coin too.

And Murdoch still owns lots of British media that’s potentially tricky for troublesome Tories. In March, a key fundraiser of the ruling Conservative Party resigned after a Murdoch-owned Sunday Times sting exposed him trading access to Downing Street dinners for donations.

Murdoch has made his wrath transparently, if somewhat elliptically, known, tweeting in March after more revelations about him that it “seems every competitor and enemy piling on with lies and libels. So bad, easy to hit back hard, which preparing”.

And in another recent tweet: “Enemies many different agendas, but worst old toffs and right-wingers who still want last century’s status quo with their monopolies.”

Only this past weekend, there were still more tantalising titbits, again in his Sunday Times: revelations that Murdoch’s quasi-daughter Rebekah Brooks — the trusted Murdoch aide he promoted from News of the World editor to run his British division — may make public her emails and text messages with her once great Oxfordshire horse-riding chum, one David Cameron. Though spring is upon London, one could feel the shiver from Downing Street after that morsel was digested.

Brooks is, many believe, the keeper of the Murdoch secrets, therefore to be protected. Murdoch’s compelling testimony to Leveson last week was notable for his ‘whacking’ of many characters in this shabby drama, from Labour ex-PM Gordon Brown, many of Murdoch’s own ex-staff, and Cameron, too. But one person Rupert Murdoch hasn’t burnt this past year is Brooks, “This One”, as he described her after rushing to her side last July as the hacking scandal — and her career — exploded.

No matter that some of Murdoch’s newspapers and former staff stand accused of crimes such as bribery, perversion of justice, perjury and interception of communications; power is about who has it and when to deploy it.

The Murdoch scandal is cancerous for Cameron. Less than two years in office and forced into coalition with the centrist Liberal Democrats in order to rule, Cameron’s Tories would lose an election were it to be held tomorrow.

A weekend opinion poll in The Guardian showed Tory support to have slumped by six points in the past month, to 33 per cent. Labour, led by the neophyte Ed Miliband, was tracking five points higher, at 41 per cent, probably enough for Labour to be elected in its own right in Britain’s simple majority, or first past-the-post electoral system. A YouGov poll in Murdoch’s Sunday Times last week gave Labour an 11-point break over the Tories, as 82 per cent of voters said Cameron’s government was out of touch with ordinary people.

Worse, there will be more revelations, and more humiliations, for Cameron as well as the Murdochs to tough out. Public evidence is continuing to be heard in the three investigations created by Cameron, including two into the police conduct and ties to News.

Cameron has Parliament, a coalition partner and a rampant opposition to answer to. Rupert only has shareholders well accustomed to him imposing his will.

“Cameron is weak,” Professor Brian Cathcart, professor of journalism at London’s Kingston University, told The Global Mail. “This is a collective investigation bigger than any previous probe into a British corporate scandal. The authorities are probably not even half-way done with it.”

And it will continue for much of this year and possibly next, extended by its own momentum, such as the fallout from last week’s disclosures of how chummy Britain’s “media minister”, one-time Tory leadership contender Jeremy Hunt, was with the Murdochs in deciding the future of BSkyB. There will be more ad hoc investigations, in Parliament and beyond, as revelations unfold.

Separately, there is the inquiry by Britain’s newly-muscular media and telecoms regulator Ofcom into whether the Murdochs and News are “fit and proper” to hold a British broadcasting licence. Then there are also the investigations and trials of the near-50 people so far arrested by police, many of them ex-News employees.

Little of this will be good for Cameron.

“They are kind of a mirror image of each other as a model of desperately maintaining power,” says Kingston’s Brian Cathcart, “in the way they have erected firewalls to protect them, firewalls that are fast being torn down.”

Cathcart cites these “firewalls” News built to prevent the phone-hacking blaze reaching the Murdochs — the rogue reporter defence, the dodgy lawyers, the executive cover-ups – now mostly in tatters.

So, too, similar construction mishaps for Cameron. First his Andy Coulson defence gave way last year, prompting the inquiries. And now Brooks seems to have decided Rupert is a better bet than her old Chipping Norton chum.

Last week Cameron saw his Jeremy Hunt defence all but collapse, and now, after the partisan pro-Murdoch posture of the four Tory MPs on the Culture Committee MPs, he could find himself in the uncomfortable position of defending their stance in Parliament, in effect a defence of the toxic Murdochs.

“It is just not popular amongst the British public to be seen to be protecting the Murdochs,” Professor Cathcart says.

But Cathcart says Rupert has something Cameron does not. An exit strategy. And Cathcart says it’s one that News Corp shareholders should insist Murdoch exercise, fast. “News Corp needs to start thinking about how to get rid of Rupert.”

Though humbled and humiliated, Murdoch could sell out of the UK as many News Corp investors demand — News Corp shares rose yesterday on that prospect — and retreat to his bunker on New York’s Sixth Avenue.

From there he’d at least be rid of — as he might see it — perfidious Poms and, though reduced, rally to wage what would be a more serious battle if the scandal meaningfully migrates across the Atlantic to Washington.

Kingston’s Cathcart says Murdoch needs to become an irrelevance to the modern functioning of the company, to become “a thing of the past.”

Yesterday’s events, Cathcart says, should dispel any notion that the Murdoch family will extend their dynasty beyond Rupert. “It’s clear that Elisabeth and Lachlan don’t want it, and it’s been proven that James can’t do it,” he says. “It’s time for Rupert to step away and for a no-name executive from the US to come in and take over. That could put a line under it.”

And be further humiliation for an 81-year-old man whose legacy may be less about his business acumen and skills as it was persuading people to provide the right results.