I think that SETTLEMENT HOUSE MOVEMENT is the movement that was instrumental in creating the scene shown in the painting.
Settlement house movement started in 1884 in Britain. The first settlement house was established and named <span>Toynbee Hall. The settlement house not only provides living accommodations to poor workers but also social services and education for them. </span> The children in the painting may be the children of these workers. They may have been left their to the care of their teachers as their parents worked for their daily living.