MPS have seized a huge haul of secret Facebook documents in a bid to unravel the Cambridge Analytica scandal.
A Commons committee used centuries-old powers to force another company to hand over the papers.
Experts believe the documents – which a US court has ordered must remain secret – could reveal the truth about Facebook’s handling of user data.
They were being held by the boss of American tech firm Six4Three, the Observer reported.
When he visited London recently, the culture, media and sport select committee demanded that he hand the documents over to Parliament.
Committee chair Damian Collins even sent the Commons serjeant at arms to the businessman’s hotel – and forced him to go to Parliament in person.
He was told that if he didn’t hand over the papers, he would be found in contempt of Parliament and could even be jailed.
A California court has ruled that the documents, which relate to a legal dispute between Facebook and Six4Three, must not be published.
But Mr Collins says he may make them public anyway – because he is protected by parliamentary privilege.
He claims they may shed light on the way Facebook protects the data uploaded by web users.
The Tory MP tweeted this evening: “The @CommonsCMS has received the documents it ordered from Six4Three relating to Facebook.
“I have reviewed them and the committee will discuss how we will proceed early next week. Under UK law & parliamentary privilege we can publish papers if we choose to as part of our inquiry.”
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Facebook told the Observer: “The materials obtained by the DCMS committee are subject to a protective order of the San Mateo Superior Court restricting their disclosure.
“We have asked the DCMS committee to refrain from reviewing them and to return them to counsel or to Facebook.
“We have no further comment.”