Prime Minister David Cameron of Britain cut short his visit to South Africa on Monday to go home for a parliamentary session.
By JOHN F. BURNS LONDON — Prime Minister David Cameron cut short a state visit to Africa as he confronted a growing scandal over his cozy ties with Rupert Murdoch’s top lieutenants in Britain and the challenge it posed to his year-old government.

Mr. Cameron, the leader of the Conservative Party, agreed to return hurriedly Monday from Africa to hold a special session of Parliament on Wednesday. He did so after coming under renewed assault from a reinvigorated Labour Party, which has repeatedly pressed him to explain in more detail his decision to hire Andy Coulson, the former editor of the now-defunct News of the World, as his communications director.
His close personal ties to Rebekah Brooks, the former head of News International and a confidante of Mr. Murdoch, are also under scrutiny. Both Mr. Coulson and Ms. Brooks have been arrested in a widening probe into hacking the phones of British celebrities, government officials, members of the royal family and victims of high-profile crimes and terrorist attacks.
Beyond the immediate politics, there was a growing sense across the country that the crisis had raised fundamental questions about the culture of collusion between politicians and the press and revealed a deeper malaise in British life that could dominate the national political scene for months or years to come.
Ed Miliband, leader of the Labour opposition, delivered a broadside against Mr. Cameron on Monday that sought to tap into the public outrage over the scandal by linking it to a series of crises in recent years — the role of the banks in the financial crisis that hit in 2008, the furor over lawmakers’ expense abuses in 2009 and now the tabloid scandal. Commentators said his goal was to weaken Mr. Cameron’s coalition government if the scandal continues to escalate, and to cast himself as a credible alternate prime minister should Mr. Cameron fall.

Mr. Miliband said the prime minister “hasn’t even apologized for hiring Mr. Coulson” and that he was “hamstrung” by his association with his former media chief and Ms. Brooks, who were among the Murdoch executives that Mr. Cameron has admitted to meeting almost twice a month during his 15 months in office. He said the country “needs leadership to get to the bottom of what happened” — a code, as some commentators saw it, for suggesting that Mr. Cameron may have to quit before the scandal has run its course.
The parade of casualties from the scandal continued to lengthen one day after the head of Scotland Yard resigned, when one of his deputies, John Yates, also stepped down. The investigation also took a grim turn when Sean Hoare, a former reporter in his mid-40s who was the first to say publicly that Mr. Coulson was aware of the widespread “phone hacking” at News of the World when he was the paper’s editor, was found dead in his north London home. The police said they did not initially regard the death as suspicious.
Mr. Hoare’s interview implicating Mr. Coulson in a New York Times magazine article last fall was one of the factors, the police have said, that prompted them to reopen an investigation into The News of the World after the probe had brought convictions and jail sentences for two men then faltered, with Scotland Yard officers saying there was nothing more to pursue.

Top police officials and senior executives of News Corporation, including Rupert and James Murdoch and Ms. Brooks, are scheduled to appear before parliamentary committee hearings on Tuesday that many expect to be part of a lengthy and open-ended inquiry into the origins of the phone hacking, the legal culpability of News Corporation officials, the failure of the police to uncover the full extent of the hacking and the connections between Mr. Murdoch’s empire and senior British politicians.
Mr. Miliband, widely viewed as a weak rival to Mr. Cameron until the recent revelations about the extent of phone hacking emerged this month, appeared to view the matters as weighty enough to form a new platform for Labour, issuing a sonorous call that sounded like a promising election plank.
“We have to ask ourselves deeper questions,” he said. “What does it say about our country? How did we let this happen? And how do we change to ensure that this does not happen again?” He said all the recent scandals in British life were caused by a lack of accountability among those in high places. “All are about the irresponsibility of the powerful, people who believed they were untouchable,” like the Murdoch executives who ran the company’s newspapers in Britain, he said.
“This was an organization that thought it was beyond responsibility,” he said. “Its power was so immense, its influence so great, from prime ministers downwards. Nobody confronted them. Nobody held them to account. Nobody seemed willing to challenge them. Not the police, not most front-line politicians, nor most of the press.”
He added: “What is a young person, just starting out in life, supposed to think when he sees a politician fiddling the expenses system, a banker raking off millions without deserving it, or a press baron abusing the trust of ordinary people?” Across Britain, he said, “there is a yearning for a more decent, responsible, principled country.”
He again called on Mr. Cameron to more fully explain his decision to hire Mr. Coulson as communications director. Mr. Coulson resigned in January as the scandal intensified.
The turning point for Mr. Cameron came with the resignations of the two Scotland Yard officers. Last week, though he had disappointed Conservatives by allowing Mr. Miliband to make the early moves in Parliament to rein in Mr. Murdoch's British operations, he steadied matters for the government by joining in demands, which were met, for News Corporation, the parent company of News International, to abandon its $12 billion bid to take over British Sky Broadcasting, the country’s dominant satellite TV network, and for Ms. Brooks to quit.
He also appointed a judge-led inquiry into the tabloid abuses, and into the ethics and practices of British newspapers, and said he would never have hired Mr. Coulson if he had not had assurances from the former editor that he played no part in the News of the World phone hacking. Then he left for South Africa.
But he appeared not to have reckoned with the bombshells thrown by the police officers as they quit under pressure marshaled by Mr. Cameron, Home Secretary Theresa May and Boris Johnson, the London mayor, all leading Conservatives. Both officers implied that if they merited losing their jobs over their befriending a former deputy editor at The News of the World, Neil Wallis — dining with him and allowing him to earn nearly $40,000 for work as a media consultant at Scotland Yard — so, too, might Mr. Cameron, over his long-term relationship with Mr. Coulson, who held an even more senior post at the paper.
Sir Paul Stephenson, the Scotland Yard chief, told a news conference on Sunday that he had not told the prime minister about his close ties with Mr. Wallis, arrested last week on suspicion of involvement in the phone hacking and bribery of police officers, because he “did not want to compromise a potential suspect who clearly had a close relationship with Mr. Coulson.”
Mr. Yates said on Monday that he had acted with “complete integrity” in his actions involving The News of the World, that he was the victim of “malicious gossip” and that if he were to be impugned for having links to Mr. Wallis, so, too, should those with links to Mr. Coulson, Mr. Wallis’s one-time boss.
In Parliament there were cries from the opposition for Mr. Cameron to quit, with one left-wing gadfly, Dennis Skinner, shouting, “When is dodgy Dave going to do the decent thing and resign?” But in South Africa, Mr. Cameron appeared unruffled, at least in public, saying that his government had "taken all of the appropriate actions" to deal with the scandal and was "making sure that Britain gets to the bottom of what has been a very terrible business."

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Sarah Lyall, Jo Becker and Alan Cowell contributed reporting.