"Those encountering Extinction Rebellion should be under no illusions about just how destabilising and extremist their agenda is. Not only is it unclear how their three formal demands could realistically be satisfied, but also it appears unlikely that their actions would end even if government committed to trying to implement them. The words of Extinction Rebellion’s founders and its posts on social media make clear that the objective is system change. This means bringing down our existing democratic system—which several of the campaign’s leading figures hold in contempt—and causing rapid economic disaster for the country. The proponents of this course of action have no serious explanations for how the country would function if their demands were implemented."

See the conclusion of:
https://policyexchange.org.uk/wp-content/uploads/2019/07/Extremism-Rebellion.pdf