It's kind of funny... the "cultured" accent was normal in the early 20th century... but then accent become more broad... especially among the media and political classes... to show their "solidarity" with the ordinary person...

UK is pretty huge... we have mostly experience with the London area (which I fondly remember for constantly having black snot in my nose.... no fog though...). Once we had a little visit out in the Cotswolds.. and that was really great!