From Wikipedia

Children Who Built Victorian Britain

The Victorian era became notorious for the employment of young children in factories and mines and as chimney sweeps. Child labour, often brought about by economic hardship, played an important role in the Industrial Revolution from its outset: Charles Dickens, for example, worked at the age of 12 in a blacking factory, with his family in a debtors' prison. In 1840 only about 20 percent of the children in London had any schooling. By 1860 about half of the children between 5 and 15 were in school (including Sunday school).

The children of the poor were expected to help towards the family budget, often working long hours in dangerous jobs for low wages. Agile boys were employed by the chimney sweeps; small children were employed to scramble under machinery to retrieve cotton bobbins; and children were also employed to work in coal mines, crawling through tunnels too narrow and low for adults. Children also worked as errand boys, crossing sweepers, or shoe blacks, or selling matches, flowers, and other cheap goods. Some children undertook work as apprentices to respectable trades, such as building, or as domestic servants (there were over 120,000 domestic servants in London in the mid 18th century). Working hours were long: builders might work 64 hours a week in summer and 52 in winter, while domestic servants worked 80 hour weeks. Many young people worked as prostitutes (the majority of prostitutes in London were between 15 and 22 years of age).