What they don't mention: this works both ways. It also stops UK citizens from moving to the EU without a work permit. If the EU member states (as that's largely a country decision) appliy the same or similar criteria many UK citizens will struggle to get a job in Europe. Language skills? Mostly lacking. Summer job in the tourist industry? Probably too low paid. Retirement in sunny Spain or France? Only if you're rich and can afford it. All of this is rarely mentioned in the press and pretty much never by the politicians. I wonder why?