Claims that James Murdoch knew three years ago that phone hacking at the News of the World was not confined to a single "rogue" reporter have been referred to the police.
Labour MP Tom Watson said he is contacting Scotland Yard after two former senior executives at the paper publicly contradicted Mr Murdoch's evidence to the Commons Culture, Media and Sport Committee earlier this week.
If the allegations by former editor Colin Myler and ex-legal manager Tom Crone were correct, he said, Mr Murdoch could face investigation for conspiracy to pervert the course of justice.
"I think this is the most significant moment of two years of investigation into phone hacking," he told the BBC. "If their version of events is accurate, it doesn't just mean that Parliament has been misled, it means the police have another investigation on their hands."
Prime Minister David Cameron said Mr Murdoch had "questions to answer in Parliament", and suggested that the management of the Murdochs' media empire is now "an issue for the shareholders".
Mr Murdoch, the head of News Corp in Europe and Asia, said he stands by the evidence he gave when he appeared with his father Rupert Murdoch before the committee on Tuesday.
He told MPs he had been unaware of an email suggesting hacking at the paper was more widespread than had been admitted when he signed off a reported £700,000 out-of-court settlement with Gordon Taylor, the chief executive of the Professional Footballers' Association, in 2008.
But in a statement on Thursday night, Mr Myler and Mr Crone said Mr Murdoch was "mistaken" and that they had informed him of the email, which had been obtained by Mr Taylor's lawyers.
Scotland Yard confirmed it had received a letter from Mr Watson asking detectives on the Operation Weeting inquiry into phone hacking to investigate. A spokesman said that it is "being considered".
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Meanwhile, Mr Cameron, speaking on a visit to Warwickshire, said News International - News Corp's UK newspaper publishing arm - needs to clear up the "mess" that has been created, adding: "That has to be done by the management of that company. In the end, the management of a company must be an issue for the shareholders of that company."
