It is unclear if the Serjeant at Arms was wearing his traditional uniform and sword when he turned up at a London hotel demanding the handover of explosive internal Facebook documents this weekend from a US businessman.

Sword or no, he seized them citing Parliamentary privilege and the social media giant’s lawyers are spitting blood: the sensitive cache is sub judice, or restricted by a US court order; they say publication would constitute contempt of court.

They were taken from Ted Kramer, an executive of defunct app maker Six4Three, who is suing Facebook. After refusing to give them up, he was reportedly frogmarched to Parliament and threatened with imprisonment.

Six4Three in turn obtained them via document discovery (the pre-trial process where evidence can be gathered from the opposite party) in the US courts, where it is seeking damages from Facebook over the failure of its $250,000 “Pikini” app, which allowed users to search Facebook for bikini photos, then zoom in on them.

The Serjeant at Arms, a partly ceremonial role that dates back to 1415, was dispatched to seize the documents by Damian Collins MP. The “unprecedented” move by the Chairman of the Culture, Media and Sport Select Committee came as Facebook CEO Mark Zuckerberg has repeatedly refused to face a grilling in Parliament.

The Committee wants him to answer questions on data privacy.

six4three facebook

What’s In the Six4Three Papers?

Six4Three in a January filing meanwhile alleged that Facebook used a range of methods, some adapted to the different phones that users carried, to gather information about users and their friends, including some who had not signed up to the social network, reading their text messages, tracking their locations and accessing photos on their phones. The documents are alleged to support this claim.

“We are in uncharted territory,” Damian Collins told the Guardian. “This is an unprecedented move but it’s an unprecedented situation. We’ve failed to get answers from Facebook and we believe the documents contain information of very high public interest.” He later hit back at Facebook, again citing parliamentary privilege.

See also: Down to the Wire: Can this Encrypted Messenger Kill Email?

The US judge presiding over the Facebook-Six4Three case has said publication of the unredacted documents held by Six4Three would constitute contempt of court.

Late Sunday November 25 Collins wrote to Facebook VP Richard Allan, saying of the sealed documents that “the House of Commons has the power to order the production of documents within the UK jurisdiction, and a committee of the House can publish such documents if its chooses to, with the protection of parliamentary privilege.”

Allan is in London this week to give evidence at what is being described as the “International Grand Committee on Disinformation and ‘fake news’” which will be attended by parliamentarians from seven nations, including Canada, Singapore and Argentina. “I look forward to seeing you again on Tuesday” Collins said.

See also: Off with Zuck’s Head?