Rupert Murdoch has told the Leveson Inquiry into press ethics that there was a "cover-up" over phone hacking at his now defunct News of the World tabloid, but that it was kept hidden from him and senior executives in his media company.
"There's no question in my mind that ... someone took charge of a cover-up which we were victim to and I regret that," Murdoch, 81, told the inquiry in London on Thursday.
Murdoch also said he had "failed" by not pressing for further internal investigations at the paper, which he closed in July last year amid outrage over the hacking of a murdered girl's phone.
"I think the senior [executives] were all ... misinformed and all shielded from anything that was going on there and I do blame one or two people for that whom I shouldn't name because, for all I know, they may be arrested yet," he said.
The paper's royal editor and a private investigator were jailed in 2007 for phone hacking, but the full scale of the practice at the tabloid did not emerge until a new police investigation was launched in January 2011.
Pressed by Brian Leveson, the senior judge leading the inquiry, about why he did not take further action over allegations against one of his biggest-selling newspapers, Murdoch said: "I also have to say that I failed."
At the judicial inquiry on Wednesday, Murdoch robustly rejected accusations that he had used his media empire to play puppet master to a succession of British prime ministers.
The appearance at the inquiry of a man who has courted prime ministers and presidents for the last 40 years is a defining moment in a scandal that has laid bare collusion between UK politicians, police and Murdoch's News Corp.
Under questioning by one of London's top lawyers on Wednesday, Murdoch appeared calm.
Asked whether he would ever have been "so undeft and cack-handed" as to ask a favour directly of Margaret Thatcher, who was prime minister at the time, he said: "I hope not ... I didn't expect any help from [Thatcher] nor did I ask for any."
Murdoch's appearance at the Leveson Inquiry on Wednesday came as Adam Smith, a special adviser to Jeremy Hunt, the UK culture minister, resigned over his dealings with Murdoch's News Corp.
The resignation came a day after Murdoch's son, James, released emails to the inquiry that showed that Smith effectively supplied News Corp with information about the progress of its bid to take full control of BSkyB.
Hunt, whose job it was to assess whether the government should approve the BSkyB bid for complete control in the face of opposition from other media groups, is also under pressure to resign.
David Cameron, UK prime minister, appointed Leveson last year to examine Britain's press standards after journalists at Murdoch's News of the World tabloid admitted hacking into phones on a massive scale to generate exclusives and salacious front page stories.
The admission last year, and the revelation that journalists had hacked into the phones of ordinary people and crime victims, forced the closure of the 168-year-old tabloid and prompted many to question whether the police had declined to properly investigate the scandal because of Murdoch's influence.
Critics argue that staff at the mass selling Sunday tabloid felt they were above the law as their boss and owner regularly dined with the prime minister and senior police officers.
Andy Coulson, a former editor of the tabloid who stood down over phone-hacking, went on to become Cameron's personal spokesman. He has since been arrested.