The thing that gets me about this story is that, as incompetent as the British police now undeniably are, there is no possible way they did not notice that the guy they were putting in handcuffs had been stabbed multiple times.
So let that sink in - you can be stood there, visibly bleeding out, and they'll cuff you simply because some random non-white person who just stabbed you accuses you of racism. No proof needed - just the accusation and immediately they'll put the cuffs on your half-dead corpse.
It has never been more clear how much the British establishment hates and literally wants its own people dead.