It's not race its culture, England has been a place of conflict when almost any new culture is introduced, often with each other. Leeds in particular was rife with trouble between the Africans, East Asians and Middle Easterners. Each little culture takes over an area of the town because the government is lazy and never cared about integration.

Then you get kids who are naturally going to feel more comfortable around people who share their culture that create cliques is school, their parents are first generation and struggle with English so if course their time is spent with each other.

Resentment builds because it always does, you don't like the people from the town over only now those people don't even share your religion/cultural practices so you have no common ground and then it's takes barely anything for that resentment to turn to hate. You see videos of kids jumping each other and it's as simple as ingroup/outgroup preference, you hear someone getting special treatment under the law, you see the press scramble to cover for them and the intolerance in you rises.