What role does setting play in a novel?

We’ve discussed the main literary elements of plot, POV/narration, character, and style, but haven’t discussed setting. Yet three of our authors (Charles Dickens, Joseph Conrad, and Virginia Woolf) have given us the same setting for their novels – the city of London. Each author is interested in particular aspects of London and uses the city as setting for their disparate visions. Think about the role setting plays in these novels, the author’s particular characterization of the city, what kinds of imagery the author associates with the city, the interactions of its inhabitants, the influence of social class, and how this portrayal of the city relates to the author’s purpose. What does London provide for these novels’ plots, characters, or themes?