No different from other accents in others counties.
Unless you speak the 'Queens English' these irregularies in grammar and pronounciation crop up everywhere.
When I go up North the way they use language is completely different.
http://www.british-ge...bits-of-Norfolk-speak
I live in Norfolk. They muddle up their verb tenses here! and pronounce a lot of words completely differently.
I am a South Londoner, south londoners don't say somefink. That is North London/Essex.
What on earth makes you think that it is different in London? Where do you come from folly fancier?