There were no child labor laws during during the Victorian Era. Even today. When 1st world countries say they have safeguarded children against labor, it's more to mean they shafted some 3rd world country to do it. The practice of tying a rope to a child and lowering them into a narrow mine shaft with nothing but a candle down to check for gasses, ore and gold veins is still a thing in some parts of the world.

The Industrial Revolution was hard. And there were a lot of people living way below the poverty line in Victorian England. Children were a source of cheap labor and were "readily available". With families unable to provide for their brood. Workhouses provided room and board to keep adults and children off the streets. And those workhouses are very much how Charles Dickens portrayed them to be. If not worse. Between the abuse, the non-existent health care system, the many ways they were poisoning each other - it was a miracle to reach your 30s.