[e17]

It's not true that one cannot hear race in British accents, it is actually quite overt. I've lived in London and Manchester and the vast majority of established Black British and South Asian British communities do speak with a noticeably different accent to other ethnicities of the same economic class living nearby. The type of London accent mostly influenced by Caribbeans since the 60s even has a proper name - Multiethnic London English

[twic]

This is heavily tied up with class, though. My middle-class professional second-generation Indian and Pakistani acquantiances speak in a way that i don't think i could distinguish from the way middle-class professional white people speak. Meanwhile, if you visit ends where Multiethnic London English is widely spoken, you'll meet white people who speak it too.