By Alex Stevenson Follow @alex__stevenson
The Murdochs' ongoing part-ownership of pay TV broadcaster BSkyB faced stinging attacks from Labour MPs Chris Bryant and Tom Watson in Liverpool this morning.
In separate speeches to their party's autumn conference the pair lambasted James Murdoch and called on regulator Ofcom to rule against him as it considers whether he constitutes a 'fit and proper person' to run a broadcasting company.
Mr Watson called News International a company "sick with corruption and criminality from top to bottom". Mr Bryant claimed NI had lied to parliament 486 times.
"Let's tell Ofcom what we think about James Murdoch. I wouldn't put him on the board of an ornamental garden," Mr Watson told delegates, to laughter from the conference floor.
"He's certainly not a fit and proper person to chair a major broadcaster."
Mr Bryant said he had hoped former News International chief executive Rebekah Brooks would be in prison by now. He added: "I hope people will go to jail for the criminal cover-up at the News of the World."
He questioned BSkyB's dominance of the pay TV market, before criticising Labour's past familiarity with senior NI chiefs.
"There's another scandal, which is that we allowed it to happen," Mr Bryant said, to applause.
"Not our finest moment. And I think in the future we should choose our bedfellows with a little more care.
He called on Labour to find some "backbone" and hoped it would no longer be a "creepy-crawly party to the media".
A panel session which featured Mr Watson saw the West Bromwich East MP admit he had feared he would pay the price for his campaigning on phone-hacking.
"I just thought this company is so vindictive they would destroy my career and I'd have to leave politics," he said. "But I thought that was a price worth paying on this particular issue."
Shadow culture secretary Ivan Lewis praised the pair, along with former deputy prime minister John Prescott, for their work in uncovering the phone-hacking scandal.
In his speech, he called for a new system of independent regulation which would see front-page mistakes rectified with front-page apologies and retractions.
Addressing Rupert Murdoch directly, he said: "Your newspapers and Sky TV are popular with millions of British people.
"However, and yes we should have said this a long time ago, Mr Murdoch, never again think you can assert political power in the pursuit of your business interests or ideological beliefs."