I think the media perpetuate the North/South divide and seem to "pit" the two against each other.
There will, of course, be examples of Southerners thinking they're better and visa-versa.
As a personal story, my DGM was a Southerner, who lived up North nearly all her life - she hated the South, it was amusing.
Then as mentioned, where is the "North"? It is banded around that Southerners think it is anything North of the Watford Gap. To me, coming from the North West (and only thinking of England, as opposed to the UK which then accounts for Scotland), the "North" doesn't begin until Chester.
As opposed to the stereotypes it isn't "grim up North" and not everyone is "posh" or has a chip on their shoulder down South, there are good and bad places and people all over the country.