There must be an upper crust British accent thenj, as well as regional. I've not heard one for some time except on the telly I mean video or radio (don't watch tv any more).
The upper crust accent is called The Received Pronunciation or the “posh” accent as most average Brits call it. Most average Brits snicker at other average/non-nobility Brits who put on the “posh” accent.