Rupert Murdoch expressed regret Thursday for his failure to halt what he called “a coverup” at his News of the World tabloid over the phone-hacking scandal that continues to engulf his media empire.

Testifying for a second day at an inquiry into press ethics, the chairman and chief executive officer of News Corp. said that the extent of hacking had been hidden from him and his senior executives, adding that they were “all misinformed and shielded.”

There was, Murdoch said, no doubt in his mind “that maybe even the editor, but certainly beyond that, someone, took charge of a coverup which we were victim to and I regret.”

At times combative, at times contrite, Murdoch has said he welcomed his two-day appearance before the Leveson Inquiry , the longest by any witness, for the chance to put “certain myths to bed.”

During his testimony Wednesday, he admitted to hobnobbing with various prime ministers during his 40 years at the center of British life, but denied ever seeking or receiving government favors.

Murdoch, 81, is arguably the most highly anticipated of the scores of witnesses to appear before the panel, which Prime Minister David Cameron set up in July in response to revelations that News of the World journalists had illegally hacked into hundreds of people’s cellphones.

Although Murdoch didn’t name names, he suggested that a “clever lawyer” at News of the World who was a “drinking pal” of reporters there was involved in the culture that allowed the coverup. On Thursday evening, Tom Crone, a former lawyer at the tabloid, issued a statement calling the allegations a “shameful lie.”

For years, News Corp. insisted the hacking was limited to one “rogue” reporter, Clive Goodman, who was briefly jailed in 2007, along with a private investigator, for tapping in to the voicemails of aides to Prince William.

Murdoch said Thursday that when Colin Myler, currently the editor of the New York Daily News, became editor of News of the World in 2007, he was given “specific instructions” to get to the bottom of what was going on.

But while Myler did introduce new regulations, Murdoch said, he “never reported back that there was more hacking than we had been told.”

Murdoch appeared appreciative when Judge Brian Leveson said that newspapers were a part of his being and that he had ink running through his veins — “Thank you, sir,” he said — but he acknowledged that “some newspapers are closer to my heart than others.”

He said he was “guilty of not having paid enough attention” to the News of the World. “It was an omission by me. All I can do is apologize to a lot of people,” Murdoch said. “I also have to say I failed, and I am very sorry about it.”

The scandal erupted after disclosures that the News of the World had illegally intercepted the voicemails of Milly Dowler, a 13-year-old murder victim. Referring to the widespread revulsion that followed, Murdoch said he could feel the “blast coming in the window.” Snapping his fingers, he said the decision to shut the 168-year-old tabloid “was done like that.”

I panicked, but I’m glad I did it. And I’m sorry I didn’t close it years before,” he said.

At the same time, Murdoch emphasized he had built a “new” company, at great cost. Over the past year, News Corp. has spent “hundreds of millions of dollars” investigating its British operations, he said, adding that the company had trawled through 300 million e-mails, 2 million of which have been flagged for closer inspection.

News Corp. is the world’s second-largest media conglomerate. Its U.S. companies include Fox Television, Fox News, the New York Post and the Wall Street Journal.

Although the company has been widely criticized for misleading the police in their initial investigations into hacking, News Corp. was now going “way beyond what the police asked,” Murdoch said.

Shortly after Murdoch finished testifying, Ofcom, the broadcasting media regulator, said it was expanding its investigation of whether the broadcaster BSkyB, which is partially owned by News Corp., was a “fit and proper” owner of a license.

The phone-hacking scandal, Murdoch said, would be a “blot on my reputation for the rest of my life.”