Half children's services money 'spent on 73,000 in care'
Half of England's £8.6bn children's services budget is being spent on just 73,000 of the most serious cases - those in care, analysis reveals.
The rest of the money is spent on the remaining 11.7 million children, says the Institute for Fiscal Studies.
The children's commissioner said help reached many children too late, leading to more ending up in violent street gangs, in care or in the courts system.
The government said it was spending a record amount on education.
The report, Public Spending on Children in England: 2000 to 2020, commissioned by the children's commissioner, is published at a time when gang violence is in the spotlight after a wave of shootings and stabbings in London.
It said while public spending on children overall had been broadly maintained over the past 20 years, millions of vulnerable children were missing out.
This was, it said, because of the huge cost of helping the relatively small number of children in extreme crisis and the fact authorities and agencies were focusing on providing the statutory services required by law. Meanwhile, the report added, spending on youth services and prevention had been cut by 60% over the past decade.
'Helped too late'
Children's commissioner for England Anne Longfield said: "While every child should receive the support they need, the economic and social costs of this current strategy are unsustainable.
"The cost to the state is ultimately greater than it should be and the cost to those vulnerable children missing out on support will last a lifetime.
"Every day we are seeing the consequences of helping children too late - in pressures on the family courts system, special schools and the care system, and in the spiralling numbers of school exclusions and the consequent increase in younger and younger children linked to violent street gangs.
"Children do not arrive in extreme need overnight and many could be prevented from getting to that point if we helped them sooner in a more effective way.
"We are, in effect, attempting to manage and contain crisis in children's lives after allowing it to escalate."
'Making up for cuts'
Councillor Richard Watts, who chairs the Local Government Association's children and young people board, said it had warned that the current situation facing children's services was "unsustainable".
"Last year saw the biggest annual increase in children in care numbers since 2010, and councils are now starting more than 500 child protection investigations every day on average," he said.
Nick Brook, general secretary of the National Association of Head Teachers, said: "Schools and colleges are now using their own impossibly tight budgets to make up for cuts to children's health and social care services. And most young people are losing out in some way or another.
"As the report says, we are attempting to manage and contain crises in children's lives after allowing them to escalate."
A government spokesperson said: "This report recognises the government is maintaining the amount spent on children's services, spending a record amount on education and making more than £200bn available to councils up to 2020 for local services, including those for children and young people.
"We are reviewing school exclusions to make sure they are only used as a last resort and this government has launched a new Serious Violence Strategy which puts a stronger focus on steering young people away from violence through early intervention.
"A further £200m programme is supporting councils to develop innovative ways to improve the lives of vulnerable children and families."