The UK Tried to Clamp Down on Migration–and Wound Up with an Unprecedented Wave
wsj.com
wsj.com
Farage campaigned against non-white immigration, fuelling the Brexit movement which was predicted to increase non-white immigration. Now he is reaping further political dividend from the issue his policy position exacerbated. It's all about narrative, and people are easily persuaded if the narrative is resonant
Nobody in office wanted to enforce what Brexit was voted for. They wanted to pay lip service to respecting it, but continue business as usual, or even go worse into the same direction Brexit was voted to get away from.
It's not a Brexit problem (especially since major EU countries have the same issues). It's a "Brexit only in name" problem.