Conventionally, a cockney is anyone born 'within the sound of Bow Bells' (St Mary-le-Bow church, in London), but rather than fixating on Dirty Den from Eastenders, Dickensian villains or Pearly Kings and Queens, perhaps we should focus rather on comedian Arthur Smith's definition, which may be nearer the mark: a cockney is simply a 'non-posh Londoner'.
Supposedly cockney rhyming slang was originally invented to outwit authority and eavesdroppers. Whether that's true or not, it remains a closed language to the uninitiated. But its humour is too good to be missed, which is, in large part, the rationale for this compact, entertaining volume.