The UK does have a few indiginous people, but they mostly live in France and Ireland now. They make up the Bretons, the Angles, The Saxons and the Celts. They got booted out by the Norsemen and the Romans in quick succession. You're right, I possibly shouldn't use BIPOC when referring to British populations - but the language and terminology gets very complex and now I use it for everything. The term here is BAME (Black Asian and Minority Ethnic) but this is coming under fire by different groups and we will be back into the mad-hatters tea party of linguistic chaos.
We're actually in complete agreement - albeit a convoluted way round. What has happened in this country is the reverse of what you have suggested. Britain has picked up a great deal of the American conversation and attempted to apply it here - where the situation is much more complicated and far more nuanced. We have far more of a class problem and class and race are not as interlinked here as they are in the states. We have a more socialist approach (free healthcare, nursery places, social housing etc) and that takes some of the edge off being poor in the UK.
One of the problems we have is inferrable from this piece. Our BAME population are mostly immigrants within the last 80 years from the Empire. In certain industries and sectors they have collected wealth, purchased houses, educated their children and have instilled a work ethic in their children that is occasionally lacking in some of our poor white families. Places in the UK that were decimated by Conservative politics in the 1980s haven't recovered. Throw in some complicated immigration of white people (Poles and Romanians) and you have a hot mess of confusing narratives that bear little relation to your country.
If we bring over the identity politics model from the US and attempt to apply it here - the evidence doesn't stack up in quite the same way. However, I will suggest my comment still stands. I think the US BIPOC population moves away from an economic socialist argument at its peril. You have a large white working class who have historically voted against their own interests and can't be relied upon to vote centre-left when hard right promises them economic security and a scapegoat. I think the demos of both our countries is rejecting the middle class discussions about racism, sexism, homophobia, transphobia etc - and the left will eat itself.
Thanks for your comment and keeping the discussion going in a positive direction. I was very glib with my response and I shouldn't have been. My apologies. I think we'll likely disagree on a great deal and agree on plenty of things, so I've followed you and I'm looking forward to finding out what insights you have about your country and mine. :o)