Um... I'm not actually British, so I'm not sure where it's from, but I think it's Oxford. Watch lark Rise to Candleford and you'll know the type I mean. They do talk about Oxford in that show, they live near there. If one of you cool British people could clarify for me??
The Scottish Highland accent is brilliant. Also the Yorkshire, Lancashire and Geordie (is that how you spell it?) accents. And I think English accents of the stereotypical 'oh my bally gosh the weather's so bally spiffing' kind are great too, though not many people actually speak like that in England at all these days.