It’s three against one for James Murdoch. That’s the latest tally of how many former News International executives have publicly accused the son of Rupert Murdoch of giving inaccurate testimony before Parliament last week.

The younger Murdoch says he stands by his testimony, but what if it turns out he fibbed? Could James Murdoch be tried for perjury?

In the United States, witnesses before congressional committees commonly testify under oath [PDF] at investigative hearings—thereby criminalizing any intentional misstatements, which are punishable by up to five years in prison.

But taking an oath to tell the “truth, the whole truth and nothing but the truth” is less common in hearings before British parliamentary committees, according to the Guardian. Though the committee reportedly considered making an exception for the Murdochs, ultimately no oath was administered.

So, even if Murdoch had lied, he wouldn’t have committed perjury. In theory, Murdoch could still be punished by fines or imprisonment if he’s found to have committed a contempt of Parliament or, in other words, done something to impede the work of Parliament.

But such serious sanctions are rare. One member of Parliament said last week that criminal sanctions hadn’t been applied to lying witnesses “in modern times.” Read the exchange between the MP and the Leader of the House of Commons, Sir George Young:

Mr David Ruffley (Bury St Edmunds) (Con): Select Committees will have a vital role in getting to the truth behind the allegations of phone hacking and other corrupt practices, but in modern times this place has not used criminal sanctions against witnesses who lie to Select Committees. In the light of the inquiries announced this week and the public interest, would it be possible to have an urgent debate when the House returns in September on why this is? Sir George Young: If a Select Committee feels that there has been a contempt, the procedure is that it makes a report to the House and then the Speaker decides whether to give it priority, and if he does it is put on the Order Paper and referred to the Standards and Privileges Committee. If that Committee finds that there has been a contempt, it has at its disposal a wide range of penalties, including fines. ... It is entirely a matter for the Standards and Privileges Committee, and ultimately the House, what sanctions should then be applied to anyone who has committed a contempt.

Murdoch testified last week that he had signed off on a phone hacking settlement with a British soccer player without knowledge of the details—and in particular, without seeing a key piece of evidence: an email laying out the extent of phone hacking at the newspaper. Two former News of the World executives have countered that statement, saying Murdoch was “mistaken”—they had personally showed him the email at the time. Several British politicians—including British Prime Minister David Cameron—have said that Murdoch should be hauled back before Parliament to explain the discrepancies.

One of the two executives, Colin Myler, also faces similar questions about inaccurate testimony before Parliament. James Murdoch himself had said when closing News of the World that company executives had misled Parliament in earlier hearings on phone hacking that took place in 2007 and 2009. Myler, along with former News International chairman Les Hinton, had testified in those hearings that there was no evidence that more than one reporter had been involved in the hacking. Hinton resigned two weeks ago from his post as CEO of Dow Jones & Co., saying his testimony wasn't meant to mislead and that he hadn’t been aware of what was happening at the company.

The parliamentary committee has said it will ask James Murdoch to respond to the allegations that his testimony was inaccurate.