Sure that's obvious (or not... depending on one's political views), but there must be some legal justification. Or can they put someone in permanent solitary confinement without giving any reason at all in Britain?

I'm reading at some sites that this isn't really true and that he wasn't literally held in a 2x3m cell for 23 hours every day. Although it's not very clear what were the actual conditions.

edit: https://www.ohchr.org/en/press-releases/2019/11/un-expert-to.... it's very vague and unspecific though..