Immigration does not lower wages, and is not a net drain on economies in general and certainly not on the uk economy. Outsourcing certainly has had an impact, along with globalisation, the internet, and as will robotics in the decades to come (a lot of jobs will melt into air in the coming decades, not stolen by foreigners but simply cease to exist).

We are certainly seeing the results of upheaval and change leading to widespread malaise, unrest, rising nationalism and xenophobia, and I fear leading to another world war, for war is the logical endpoint of blaming foreigners, competitive devaluation and beggar thy neighbor economics.

I would urge you to study the demographics of voters in the referendum though, they were very mixed, the only clear split was urban (lots of immigration) pro-eu vs suburban/rural pro-exit. I’d strongly dispute that Brexit was some sort of rational revolt of the working class (who mostly live in cities) against an invasion of polish plumbers as you describe.

Like America First it will not end well, and certainly won’t help structural problems in the economy or dying industries. That’s a matter of National govs disgracefully neglecting their population, and as we’ll see, nothing to do with immigration.