> carrying a non-traditional British culture in Britain
Define "traditional British culture".
Not really, since first racism implies considering the other race inferior (except of merely unwanted in your own country), and second because foreign cultures usually don't grow on a domestic population, but come in trough immigration.
Of course some immigrants can perfectly adopt the local culture, but those are not the kind of immigrants the anti-immigrant people worry about or what they believe is happening in any large number.
>Define "traditional British culture".
Like all cultures it's a constellation of things, not all present or shared at all times by all members of it, that has developed historically.It doesn't have a mathematical style, absolute definition, but one knows it when they encounter it, the same way they can tell Basil Fawlty, tea, shepherd's pie and Punch and Judy are in it and bluegrass, wabi-sabi, yodelling and Takeshi Kitano are not.
Visit 'Britain' - then visit 'France' and you'll get an idea of the panacea of cultures and sub-cultures within those two nations, that are quite distinct from one another, most of which could be very readily labeled as either 'French' or 'English'.
And that would only be two of many nations.
Yes - culture and ethnicity actually exist in the world.
That's what actually makes it 'diverse'.
It's just that the too notions usually coincide (people of different ethnicity would usually either be recent immigrants themselves or children of immigrants).
Precisely, they don't want people that are not historically from Britain to come there from outside the country, and they are not particularly happy with those that already came and have children who've been born in Britain etc either.
(And perhaps even more so about ethnicity it's about culture -- they don't want people carrying a non-traditional British culture in Britain).