Bow Bells which mark the area of true Londoners 'are being drowned out by capital's noise pollution' | Mail Online
Of course, people with the accent that would be identified as 'Cockney' were born outside this area too, and now adays many born with the green area (there are no maternity wards in the blue area) are just as likely to be Londoners or say West Indian or Bengali background, with more of a Dizzee Rascal type accent, but an interesting article nonetheless.