*For those saying all cockneys are from East London, that is not the case. St Mary-le-Bow church is in the City of London, and historically the bells could be heard for miles in all direction.
I have seen that a lot of people think the Bow Bells were actually located in Bow (which is in East London); perhaps this causes part of the view that all cockneys are from the east, although I suspect it has more to do with East London having more working class areas in proximity to the City than other directions.*
Pedant alert!
*You can have an accent and still speak grammatically correctly. I don't buy into this saying "Was you ill?" or "Have I went mad?" being dialect - it's not. Dialect is different words and phrasings used around the country. We have LOTS in Scotland, hubby who is from Merseyside says something old fashioned is "ant-wacky" which is a Liverpool dialect word.
It's not snobbish to want your children to grow up speaking correctly and "standard" English. I will correct husband when says "Who did you get that present off?" and hate the fact that the Scottish government is trying to push Scots dialect which in many cases isn't dialect at all, it's just slovenly speak. Saying "hoose" instead of "house" or "dinnae" instead of "don't" isn't dialect.*
Agree with all of that ^^ I am driven mad by the local 'I brought this at the weekend' when someone means 'bought'. It's not dialect, it's wrong and it's lazy. Using words such as cwtch, haway and rhyming slang are all examples of dialect as opposed to local pronunciation/accent.
A friend has a local accent and says 'we done' rather than 'we did'. Her DH has no accent and speaks correctly. Both DCs speak correctly with little discernible accent.