[eldaisfish]

I see now why people downvote your comments.

Please, if you do not understand the indian caste system, don't use that term, even in the context of a comparison. This is like comparing a balloon popping to a thermonuclear explosion. The scale, history, and implications are entirely different.

What you are referring to is xenophobia, not a caste system. Xenophobia can manifest in many different ways, only one of which is racism. Are you going to seriously argue that west germans and dutch people are two entirely separate ethnicities? Yet, go to the Netherlands and Hans Muller will likely be treated differently compared to Jan van Assen. The two are almost certainly indistinguishable on the surface but their names give away their origins. This is what you are getting at, but the differences between ethnicities are not sharp, rather they are a smooth continuum. Xenophobia relies heavily on perceptions. Often, differences are difficult to perceive, but sometimes they are, as in the case of Japan which is famously a monoculture.

As a counter to your last point, the UK was and is at the forefront of integrating immigrant groups into mainstream society. Most historical immigrants to the UK are well settled, although there is now a renewed push for racism and xenophobia in politics.