"In another exceptional move, parliament sent a serjeant at arms to his hotel with a final warning and a two-hour deadline to comply with its order. When the software firm founder failed to do so, it’s understood he was escorted to parliament. He was told he risked fines and even imprisonment if he didn’t hand over the documents." Wow. I've never heard of the British parliament being this assertive before.
I am surprised that he actually complied with this order, especially as the article says the documents were under a US court order restricting their dissemination/publication, but maybe what happened is the Serjeant at Arms appeared with these scary warnings, his lawyers didn't know quite what to do, so they just did what they were told even if they probably didn't have to.
It will be interesting to see what the US court makes of its order being broken due to the order of a foreign legislature.
-- A source on the status of these powers: https://www.bbc.co.uk/news/uk-politics-18875266