Once you remove the outliers that are London and the Southeast (there isn't a similar subnational comparison that can be made within the US), developmental indicators between much of the US and the UK are the same.
2. After seeing the riots in Belfast last night where rioters specifically targeted and burned the homes of Black residents [1], I'd be inclined to agree that the United Kingdom does have some hallmarks of Mississippi, and in some sense is worse. We haven't had targeted race riots in the US for decades. The UK has had 3 in the last year.
[0] - https://globaldatalab.org/shdi/table/shdi/USA+GBR/?levels=1+...
[1] - https://www.bbc.com/news/live/cr47x99k5n6t?post=asset%3Ab5f8...