Kind of like Brexit. Yeah, screw the EU, we are going to bust out. Oh wait.
Are you predicting that Brexit won’t happen?
UK poster here. Brexit happened in January. What you're reading about now is the end of the transition period, which expires at the end of the year.
Can confirm it's a massive mess, but it's looking like it will end with a free trade deal (despite what they said last week) or probably some kind of "probation period" for the rest of the Union - Northern Ireland is already going to get a reprieve because of the reasons mentioned above.
As for secession, I think the UK has shot itself in the foot with Brexit but I imagine Texas would have a much harder (and worse) time leaving the United States than Great Britain did leaving the EU. It's closer to Scotland's Independence movement if you want to make a similar analogy.
edit: Worth noting though, that the overall points VG are making are correct. Leaving the EU could mean many different things. The Tories have shot down Brexit deals because "they weren't Brexit-enough", despite suggesting during the Vote Leave campaign that we would still remain in the single market (which is a British invention, largely). The official Tory campaign during the referendum was, by the way, to stay in the EU. It was poorly planned because David Cameron is an idiot. There's a lot of diverse stuff happening under the hood, as it were, so I wouldn't bandy about Brexit as a secessionist movement per say.