Doing a PhD at an English university, I think I heard only one postgraduate or faculty member with a strong English regional accent. There were a couple of Scots, and a few people with mild northern English accents, but only one strong one that I remember. I couldn’t know whether this was due to discrimination, but I’m sure it contributes to ongoing discrimination, by making it hard to associate someone with a strong regional accent with intellectual authority.

I would also guess that a lot of racism in the UK is modified by accent. A brown guy speaking RP will be perceived far differently than one with a brummie accent - and that’s before you get to foreign-looking people with foreign-sounding accents.