Earlier quoted context omitted.
> a British accent Hmm.... Scottish, Welsh, Irish (Nor'n) or English? If English, North or South? If North, which city? Brummie? Scouse? If South, London? Cockney or Multicultural London English [0]? [0] https://en.wikipedia.org/wiki/Multicultural_London_English
Need to increase your granularity a bit. I live in Wexford Town, Ireland, and the other day I was chatting to a person that told me their old schoolmates from Castlebridge are making fun of their accent changing since moving from their hometown. Castlebridge is 10 minutes away by car. Madness!
https://accentbiasbritain.org/accents-in-britain/
Also, we have yet to define precisely define what is meant by 'British'. This probably needs a "20 falsehoods people believe about..."-type article.