Well, the establishment was in fact screwing them over. Honestly, good for the Brits. They might still be screwed by going it alone, but they were certainly screwed had they continued acting as an appendage of German and Belgian interests and dumping ground for refugees. Social welfare states cant have open borders, unfortunately for Europe noone has bothered to tell
the European Council.

For who could be free when every other man's humour might domineer over him? - John Locke (2nd Treatise, sect 57)