James Murdoch insisted Tuesday that he knew little about the scale of phone hacking by people working for the News of the World, as he continued his fight to limit the damage the scandal does to him and his family's media empire.
Underlings did not tell him how pervasive it was when he took over News Corp.'s British newspaper publishing arm, he said.
He agreed with a suggestion that the reason was because they knew he would put a stop to it.
"I think that must be it, that I would say, 'Cut out the cancer,' and there was some desire to not do that," he told the Leveson Inquiry into press ethics.
Former Murdoch employees testified earlier that they told him about the problem.
He was testifying before an independent British inquiry into journalistic ethics prompted by phone hacking at the defunct News of the World, once the flagship British Sunday tabloid of News Corp.
The scandal has reverberated through the British political establishment, led to dozens of arrests on suspicion of criminal activity and forced News Corp. to pay hundreds of thousands of pounds in compensation to the victims of phone hacking.
Tuesday's hearing revealed the depth of the links between the Murdoch family and British politicians, with Murdoch saying he had had drinks with David Cameron at a pub before Cameron became prime minister and dined with him once he was in office.
Leveson Inquiry lawyer Robert Jay pressed Murdoch over the extent of his contact with politicians as the company moved to take full control of satellite broadcaster BSkyB, a bid that collapsed because of the phone-hacking scandal.
Evidence published Tuesday suggests that News Corp. was getting inside information from the government minister with the power to approve or block the acquisition, Culture Secretary Jeremy Hunt.
Hundreds of pages of e-mails painted a picture of a back channel between Hunt's office and Frederic Michel, a top Murdoch employee.
Michel told Murdoch in January 2011 that he had gotten "absolutely illegal" information about government plans related to the takeover plan, the e-mails show.
Prime Minister Cameron has full confidence in Hunt, his spokesman Craig Oliver told CNN after the Murdoch testimony concluded.
Hunt's portfolio includes the London Olympics, which are now less than 100 days away.
James Murdoch and his father, Rupert Murdoch, have been hammered over the past year about what they knew about phone hacking by people working for them.
Rupert Murdoch is scheduled to appear Wednesday and perhaps Thursday morning at the inquiry.
The younger Murdoch has already been called twice to testify before British lawmakers and resigned from a number of top management positions at British subsidiaries of his father's media empire.
He and his father have always denied knowing about the scale of phone hacking, which police say could have affected thousands of people, ranging from celebrities and politicians to crime victims and war veterans.
James Murdoch said Tuesday that he had no reason to look into illegal eavesdropping by his employees when he took over the company's British newspaper subsidiary in December 2007.
A News of the World reporter and a private investigator had been sent to prison that year for hacking the phones of the staff of Princes William and Harry, but Murdoch said he had been assured that the problem went no further.