That is one thick accent. And it's not a commonly heard accent here in the US.
I think we generally believe that Brits either speak like Prince Charles, or have some Cockney chimney sweeper accent.
Boy was I mistaken.
I used to enjoy Andy Capp comics, and would ask my GF what he was saying in certain strips.
She told me, boop, you have to understand that Andy is from North England.
She knew that implicitly. I had no idea.
My wife is from Norwich, and like other parts of Britain, has its own accent. I can barely understand my brother-in-law who grew up in Norwich. My wife has lost a lot of her accent after living in the U.S. for about thirty years. The official name of the “posh” accent is The Received Pronunciation. There are far more regional accents in Britain than in the U.S. or any other English-speaking country. For instance, Australians have basically one pronunciation/accent from one end of the country to the other. According to sources I’ve heard tell me.