Rupert Murdoch rejected accusations on Wednesday that he used his media empire to play puppet master to a succession of prime ministers, electrifying a media inquiry that has shaken the government and unnerved much of the establishment.

The appearance of the world's most powerful media mogul is a high point in an inquiry which has laid bare collusion between ministers, police and Murdoch's News Corp, reigniting concern over the cosy ties between big money, the media and power in Britain.

Murdoch, 81, was immediately asked about his relationship to politics and British toffs, a reference to his regular attacks on Britain's gilded establishment, which the Australian-born tycoon has lampooned as snobbish and inefficient.

He said he was keen to put straight some myths about him.

I have never asked a prime minister for anything, Murdoch said calmly when asked about his links to former Prime Minister Margaret Thatcher, one of his favourite British leaders.

Cameron, under intense criticism for his own ties to Murdoch and facing calls to fire a senior minister who stands accused of breaking rules to help News Corp, told a raucous session of parliament on Wednesday that politicians from all parties had got too close to the magnate.

I think on all sides of the House there's a bit of a need for a hand on heart, he told a chamber of jeering opposition lawmakers. We all did too much cosying up to Rupert Murdoch.

Cameron and at least two former Prime Ministers are expected to appear for questioning in the coming months.

Some politicians had expected the magnate - courted by prime ministers and presidents for decades - to come out fighting, having been on the back foot for almost a year over a newspaper phone hacking scandal that has convulsed his empire.

But Murdoch appeared calm and laconic, at times provoking chuckles from some of the 70 lawyers, family members and journalists packed into the Victorian gothic courtroom when he cracked jokes about the destruction of unions and a disgraced former British minister who lied in court.

The man who has for years portrayed himself as an underdog, said he had simply tried to shine a light on the country on the behalf of the working classes.

I think that it is fair when people hold themselves up as iconic figures, or great actors, that they be looked at, he said. I don't think they are entitled to the same privacy as the ordinary man on the street.

But he admitted that his opinion had been carried by his Sun newspaper, one of his favourites for years. I'm not good at holding my tongue, he said. If you want to judge my thinking, look at the Sun.

He also shed some light on recent British political history, saying that then Prime Minister Gordon Brown had reacted to the news that the Sun newspaper would be withdrawing its support for the Labour party by threatening to declare war on News Corp.

I did not think he was in a very balanced state of mind, Murdoch said.

Asked if as reported he had initially found Cameron to be lightweight, Murdoch replied: No. Not then. He had also not found it strange when Cameron took time out of his own private holiday to meet him on a yacht off a Greek island in 2008.

I've explained that politicians go out of their way to impress people in the press, he said.

As the questioning went on Murdoch started to appear agitated. The session was adjourned in mid-afternoon and will resume on Thursday.

Murdoch biographer Michael Wolff told Reuters he thought the News Corp boss had performed brilliantly.

I'd like to see fireworks as much as the next guy but that hasn't happened, he said. Murdoch is very much on his game.

PUBLIC ANGER

Cameron ordered judge Brian Leveson to conduct a media inquiry last year to examine the explosive revelations that staff at Murdoch's News of the World tabloid used widespread illegal phone hacking to generate exclusive stories.

The scandal, which dominated the political agenda for much of last year, exposed the close ties between the upper echelons of Britain's establishment and provoked a wave of public anger. Politicians who had previously courted the media owner lined up to condemn his involvement in Britain.

U.S.-based News Corp, owner of Fox Television and the Wall Street Journal, eventually withdrew its $12 billion bid to buy the 61 percent of satellite broadcaster BSkyB that it did not already own after intense political and public pressure because of the wrongdoing at its newspapers.

On Wednesday the scandal claimed a political scalp at the heart of the government when an adviser to the media and culture minister quit over the suggestion he had helped News Corp in an attempt to secure the BSkyB takeover.

Explosive emails suggesting Media Secretary Jeremy Hunt had sought to help Murdoch in his business dealings - revealed during questioning of Murdoch's son James on Tuesday - go to the heart of the accusations that Murdoch wields too much influence, creating a company culture that rode roughshod over rules.

The emails appear to show that Hunt briefed News Corp on the thinking of regulators and leaked confidential information, while at the same time acting for the government in deciding whether to approve the takeover.

The minister, previously seen as a rising star in the right-leaning Conservative Party, said he would clear his name.

The admission ramped up the pressure on Cameron, who has been hit by a string of mistakes in recent weeks and is enduring his worst run since becoming Prime Minister in 2010. To compound his problems, economic data released on Wednesday morning showed that Britain had slipped back into recession.

He also has his own questions to answer over his relationship with Murdoch, after he employed as his personal spokesman a former Murdoch editor who was forced to quit over the hacking scandal

Murdoch was the first newspaper boss to visit Cameron after he took office in 2010 - entering via the back door - and politicians from all parties have lived in fear for decades of his press and what they might reveal about their personal lives.

Labour politician Chris Bryant, who accepted damages from Murdoch's British newspaper group after the News of the World admitted hacking his phone, told Reuters the media mogul had dominated the political landscape for decades.

You have only got to watch Rupert Murdoch's staff with him to see how his air of casual violence intimidates people, he said. His presence in the British political scene has similarly intimidated people by offering favour to some and fear to all.

(Writing by Guy Faulconbridge and Kate Holton; additional reporting by Paul Sandle, Paul Hoskins, Drazen Jorgic and Estelle Shirbon; Editing by Peter Graff and Giles Elgood)