UK Home Secretary Suella Braverman is on the very-far-right-authoritarian side of the government, and she's been very vocal in her support for Israel. It wouldn't surprise me at all to learn that detentions like these are at her direct instruction. Perhaps not at a "lift this guy" level, but certainly at the level of directing the authorities to step up their harassment of people.
But I couldn't find any tweet that openly calls for violence either way. Mostly seems to be reactions and criticism about Israel's ongoing killing of civilians in Gaza, which would hardly count as terrorism (edit: well, at least shouldn't).