The most disadvantaged children come from homes where there is no community. They go to giant schools where they are just a face in a crowd. The schools are too big for the teachers to know each other, let alone all the pupils. Consequently, the pupils experience no sense of commuity within the school. They do not even experience the community of a fixed class, as they are put in one set for one subject, and another set for another subject, each lesson being with a different group of pupils.
The result of this is less efficient learning and no discovery of social responsibility as members of a group overseen by an adult.