Rupert Murdoch rejected accusations yesterday that he used his media empire to play puppet master to a succession of British 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 explode some myths about himself.

"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.

Prime Minister David Cameron, under criticism for his own ties to Murdoch, and facing calls to fire a senior minister accused of breaking rules to help News Corp, told a rowdy parliament yesterday that politicians from all parties had got too close to the magnate.

"I think all sides of the House need hand-on-heart," he told jeering opposition MPs. "We all cosied up too much to Rupert Murdoch."

Cameron, together with at least two former prime ministers, is 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 drawing 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 behalf of the working classes.

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

He admitted that his opinions 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 light on recent British political history, saying that former prime minister Gordon Brown reacted to the news that The Sun would withdraw 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.