Why could Charles Dickens describe the suffering of London's poor so vividly and accurately?

Dickens knew poverty and suffering while working at a blacking factory (which made shoe polish) when he was 12. His parents compelled him to work there when they lost all their money; shortly after he began the job, his father was confined to a debtor's prison. Dickens lived in a squalid little room close to the factory and had little money for food, since he gave most of his earnings to his family. Though this lasted only several months, his life was scarred by the experience and his writings would thereafter reflect his empathy with the disaffected and poor population of London.