It's more than just immigration, Neo. It's autonomy in the UK's case, along with the same legislation on trade Bernie Sanders as well as Donald have green lighted.
Fam, the UK proposed much of the laws and regulations that the EU follows. They're gonna have a hell of a time getting into the European Economic Zone, which is arguably the best route. And then they're back where they started, on some level, because they'll HAVE to follow EU trade regulations.