The number of children in care is increasing because children are staying in care for longer, experts told MPs.
The number of children in care is expected to reach almost 100,000 by 2025, the education select committee heard on Tuesday.
Currently the number stands at just over 80,000.
Children’s Commissioner Rachel de Souza also told MPs that local authorities should act as "pushy parents" for children in care - and even take children to school in areas of gang activity.
The committee heard that although fewer children are going into care, fewer are also leaving because they have more complex needs which is one of the reasons why the numbers are increasing.
Other reasons include changes in the birth rate, a significant rise in unaccompanied asylum seeker children and policy changes designed to keep children out of the prison and mental health secure systems.
Yvette Stanley, National Director for Social Care at Ofsted, said there are a growing number of adolescents in care because children are coming into the system at an older age, having suffered more significant harm and needing care for longer.
Children’s Commissioner Rachel de Souza said: “We have fewer children in the last three years coming into care, fewer leaving... That’s why the number is growing.”
Asked about the six percent of youngsters in children’s homes not in education or training, Dame Rachel said: "We need the local authority to really... They need to be like the pushy parent for the children. They are the corporate parent."
She added: “We need proper parenting of these children, even if it’s a corporate parent, to get them in the right schools, to get them in good and outstanding schools, they have a right to be there... To make sure that there is a proper plan so the child can be successful in school.
"When you talk to children on the ground, it’s things like, ‘Oh I can’t go to school because there’s gangs’. Well, let’s make sure that those children are taken to school, solve the problems."
Ms Stanley added some families are living in “dire economic situations”. She added: “We are seeing children living in frankly very poor housing conditions and the stresses that puts on families.”
MPs on the education committee are holding an inquiry into children’s homes.