His speech does not make sense. The zombies are the cockneys, they are the Eastenders, hence the football hooligan joke.
Also the East end of London , with the docks and cheep run down housing has always been a magnet for immigrant communities, be it the East European Jews at the turn of the 20th century or the large Bangladeshi community around Brick Lane. The economics of London has also changes with the Dockland development of the abandoned docks turning the area into a part of the financial district with an influx of city workers, development and increasing property values. The disappearance of the docks also saw the disappearance of the jobs the sustained the white working class that made up the Cockneys. Yes, they are disappearing, but they only appeared as a distinct group about a 130 years ago, which is a short time in the history of London.