I don't know much about Brexit except that the EU was planning to ban tea kettles and had regulations on the proper curve in bananas.
Somewhere awhile back, I read a warning that the "tribes" would revolt, i.e. that the local ethnic groups would want to separate from empires, in the same way that the Ukraine et al left Russia and Yugoslavia went kaput.
But with an outsider, Duterte, winning in the Philippines, and now the rural and working folks in the UK are giving a strawberry cheer against the EU, I wonder if the Trump will be the next big thing.
Don't ask me: I only get US news from the MSM and the blogosphere and it's hard to figure out the grass roots opinion from 8000 miles away.
as for Immigrants: I think maybe the problem is not immigrants per se as that the elite want to use "multiculturalism" to destroy the self reliant and independent culture of the US or UK, where folks dare to think they should have a say in what laws are passed. And to destroy Christianity, of course.
Assimilation is the answer.
I suspect my relatives in the UK are more pro British than many elites who love to run the place, but alas, the brexit types do include some who object to foreigners...