These people were always there. Previously they were regarded as oddballs who admired Enoch Powell and you were unlucky if you ever found you had to talk to any of them. Nowadays, especially after Brexit, their views are more often heard and they are shown more respect than they ever deserved.
I suspect MSM is largely to blame, especially down in England. There are a number of newspaper owners who probably lean more towards the Reform Party but realise that only the Tories are electable. Every time some right-wing populist has anything to say, in the UK, the USA or Europe, they get far more coverage and encouragement than they should.