I live in London. Over 37% of all Londoners are foreign born immigrants, under 45% are white British so less than half. In my borough over 20% of the population are black Caribbean. This sort of mixture has long been a London feature going back centuries and we have always prospered, not in spite of it but because of it.
Immigration made the USA the greatest nation on earth, and in our own example, London, where well over a third of the population is foreign born, it's by far the most successful part of UK economy and has long carried the rest of the country financially.
So what are people scared of? Getting rich?
I believe that to compare the present imigration situation into the UK with that of historical imigration into the USA gives a false impression. The USA is / was a vast land mass with an abundance of natural resource, materials and food producing capacity. This was set against a very low population. In short, the USA prospered as the population grew because they were able to exploit their natural resources more fully.
What we have here, now, is different. I don't hold any malice or dislike for people who come from a different ethnic background, culture or country to me. I'm that sure some of them are very nice people and I'm sure that some of them are very nasty people, just like our home-grown citizens here. But, I don't think that us, here, the UK, or whatever you want to call it can support an influx of people from other nations. We aren't like the USA, we can't grow enough food, we can't provide ourselves with enough energy, the schools are too full, hospital A&E departments are crumbling, the police are over stretched, social workers have too many cases each to provide a service, the prisons are full, there are more people than jobs. There are other examples, but what I am saying is, there are too many people. Regardless of whether they are English, Irish, Scottish, Romanian, Polish, French, German, Bulgarian, or any country, there are simply too many people here and to allow more people to come into the country makes no sense at all. Nearly all of our problems and everything that is wrong in the country can be traced back to too many people.
Apparently, the late Middle Ages, directly after the plague, was a good time to live in Europe. Low population. We will return to low levels of population again within 100 years, that is a mathematical certainty.