James Murdoch insisted again today that he was not originally told of evidence suggesting phone hacking was widespread at the News of the World.
The media mogul repeated his denial of claims that the paper's then-editor and legal manager informed him of the "For Neville" email, which appeared to contradict the previous stance that the illegal practice was confined to a single "rogue reporter".
Murdoch suggested News of the World executives may have been reluctant to tell him about the extent of hacking for fear he would have ordered them to "cut out the cancer".
In evidence under oath to the Leveson Inquiry, he maintained his stance that in 2008 he was not shown the "For Neville" email, which contained transcripts of intercepted voicemails apparently intended for the paper's chief reporter Neville Thurlbeck.
He again disputed the evidence of former News of the World editor Colin Myler and legal manager Tom Crone that they informed him of allegations that hacking was "rife" at the paper.
Murdoch referred to notes of a phone call about the problem between Myler and external solicitor Julian Pike on 27 May, 2008, which concluded: "James wld say get rid of them - cut out cancer."
He told the inquiry: "This is something I have struggled with as well, which is, why wouldn't they just come and tell me.
"I was a new person coming in, this was an opportunity to actually get through this.
"I think that must be it, that I would say, 'cut out the cancer', and there was some desire not to do that."
Myler and Crone say they showed Murdoch the "For Neville" email at a meeting on 10 June, 2008 to discuss settling a civil claim brought by Professional Footballers' Association chief executive Gordon Taylor over claims the News of the World hacked his phone.
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In the end Murdoch approved a confidential out-of-court settlement with Taylor for £425,000 plus costs.
Robert Jay QC, counsel to the inquiry, asked whether Myler and Crone discussed the potential damage to News of the World publisher News International's reputation if the case went to a public trial.
Murdoch replied: "It was referred to that it would be in the best interests of the business not to have this matter from the past, from a few years ago, dug up and dragged through the court.
"But it was more in the spirit of that here was an issue that happened a few years ago, it's all in the past now, it's all finished, and we don't want to have to go through that again."
But Jay suggested: "The point was that this was new, that the Gordon Taylor litigation would create the possibility, indeed the probability, of fresh reputational damage to the company because it involved others at News International."
Mr Murdoch replied: "I follow your question, but that is not what I was told at the time."
The media boss was also asked about a chain of emails sent to him by Myler on 7 June, 2008, which contained warnings that Taylor had evidence that at least one other News of the World journalist was involved in hacking.
He said he received the message on a Saturday, when he was with his young children and had just got back from Hong Kong, and replied to it within minutes without reading the full email.
Claims that hacking was widespread at the News of the World arose again in a July 2009 Guardian article.
Murdoch said he asked his executives about the rival newspaper's allegations, but was told "that it wasn't true, that there was no other evidence, that this has been investigated to death and this is a smear".
But he admitted it is now clear that News International failed to pick up on the legal risks posed by its papers' methods of finding stories.
He told the inquiry: "Knowing what we know now about the culture at the News of the World in 2006 - well, at least that we know about the alleged widespread nature of these poor practices - it must have been cavalier about risk, and that is a matter of huge regret."
Earlier James Murdoch admitted to meeting David Cameron 12 times while the Tory leader was in opposition.
He also told the inquiry the News of the World should not have run the Max Mosley "Sick Nazi Orgy" story, which led to the former Formula 1 boss receiving more than £60,000 in compensation.
Labour MP Tom Watson, one of News International's chief critics in Parliament, has described James Murdoch's evidence as "fascinating".