When I went to college I was asked more than once which public school I'd attended. I don't talk posh but I suppose I sound posh to people from the North and the dominions.
Coupon was so January 2012...... I was born in Essex but my parents talk properly, ie posh Southern.. My flow is very stop start Captain Kirk and with a hint of South African, i use rhyming slang and mimic people from Ulster.... I hate Northern Leeds type White Rose accents the most and Mancs... Geordies just sound thick and Scots sound like street drunks or bad politicians .