"Research has shown that the average age at which children started work in early 19th-century Britain was 10 years old, but that this varied widely between regions. In industrial areas, children started work on average at eight and a half years old."
"Research has shown that the average age at which children started work in early 19th-century Britain was 10 years old, but that this varied widely between regions. In industrial areas, children started work on average at eight and a half years old."
https://www.bl.uk/romantics-and-victorians/articles/child-la...
And the first laws limited children to 12 hours work:
https://en.wikipedia.org/wiki/Factory_Acts