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James Murdoch defended his record at the head of his father's scandal-tarred British newspaper arm Tuesday, saying that subordinates prevented him from making a clean sweep at the now-defunct News of the World tabloid.

Speaking under oath at Lord Justice Brian Leveson's inquiry into media ethics, Murdoch repeated allegations that the tabloid's then-editor Colin Myler and the company's former in-house lawyer Tom Crone misled him about the scale of illegal behavior at the newspaper.

Leveson asked Murdoch: "Can you think of a reason why Mr. Myler or Mr. Crone should keep this information from you? Was your relationship with them such that they may think: 'Well we needn't bother him with that' or 'We better keep it from it because he'll ask to cut out the cancer'?"

"That must be it," Murdoch said. "I would say: 'Cut out the cancer,' and there was some desire to not do that."

The 39-year-old Murdoch said that at the time he had no reason to doubt his subordinates when he took over at News International, which published the News of the World, saying he had repeatedly been told that nothing was amiss.

"I was given assurances by them, which proved to be wrong," he said.

Revelations that reporters at the News of the World had hacked into the phones of hundreds of high-profile people, including a teenage murder victim, pushed Murdoch's father Rupert to close the 168-year-old newspaper, triggered three U.K. police investigations, led to more than 100 lawsuits, and launched Leveson's inquiry into media practices.

James Murdoch has found himself sucked into the center of scandal, with critics saying that he should have found out about the wrongdoing once he took over at News International in December 2007.

The uproar over illegal behavior at the News of the World has already scuttled Murdoch's multibillion pound (dollar) bid for full control of satellite broadcaster British Sky Broadcasting Group PLC. He resigned from his post as chairman earlier this month "to avoid being a lightning rod," he said.

Murdoch's relationship with politicians also came under scrutiny Tuesday.

The American-born News Corp. executive revealed that he'd told Conservative leader David Cameron that The Sun newspaper would endorse the Tories' election bid at a meeting at the George club in London on Sept. 10, 2009.

The top-selling paper's endorsement of Cameron's Conservatives was a blow to Britain's Labour Party — and critics claim that it helped secure Tory approval for the potentially lucrative BSkyB bid after they won the election in 2010.

Murdoch denied the charge Tuesday.

"I would never have made that kind of a crass calculation," Murdoch said. "It just wouldn't occur to me."

Murdoch acknowledged talking to Cameron about it at a Christmas dinner in 2010 — after the Tory leader had been elected prime minister — but said it was "a tiny side conversation ahead of a dinner."

"It wasn't really a discussion, if you will," Murdoch said.

Rupert Murdoch, who is still chairman and chief executive of News International's parent company News Corp., is scheduled to appear before the inquiry on Wednesday.