"just" The complete agreement of every EU nation is required to un-invoke article 50, because there are no provisions for it. Now, they'd likely do it, but tha

"just" The complete agreement of every EU nation is required to un-invoke article 50, because there are no provisions for it. Now, they'd likely do it, but that isn't a certainty, especially as the UK arguably gets a lot more out of the EU than most other member states relative to investment.