Failing children's services that are putting the lives of young people at risk will now be taken over by other councils and charities, Prime Minister David Cameron has announced.
Powers to trigger emergency inspections of social services departments following complaints from whistle-blowers or evidence of poor leadership are also set to be bolstered under the reforms.
Experts will immediately be sent in to run Sunderland City Council's unit after inspectors found "serious and widespread" failings and other local authorities in England will follow.
Mr Cameron said the state is "failing" some of the country's most vulnerable children but vowed the changes would ensure that "not a single child is left behind".
"Children's services support the most vulnerable children in our society," the Prime Minister said.
"They are in our care; we, the state, are their parents; and we are failing them. It is our duty to put this right; to say poorly performing local authorities: improve, or be taken over. We will not stand by while children are let down by inadequate social services.
"This will be one of the big landmark reforms of this Parliament, as transformative as what we did in education in the last. And it shows how serious we are about confronting state failure and tackling some the biggest social problems in our country. Together we will make sure that not a single child is left behind."
Local authority departments judged inadequate by Ofsted will have six months to improve or they will be taken over in a system that mirrors Government reforms to tackle failing schools.
Top performing councils, experts in child protection and charities will be sent to run the worst units and will have the power to oust members of staff.
Ofsted reported "serious and widespread" failings in the care of vulnerable children in Sunderland. Its children's services will now become a voluntary trust.
Commissioners will go into Norfolk and Sandwell children's services immediately with a view to taking them over within a year.
NSPCC chief executive Peter Wanless said: "Tackling child abuse is the greatest challenge of our generation. So an increased Government focus alongside these reforms, to help reduce the risk of harm to vulnerable children, are very welcome.
"Child protection is often a huge and complex area but too frequently some services have failed in this crucial duty; when this happens swift action is an absolute priority to prevent tragedies that shame us all.
"And we need to ensure that if tragedy does befall a child, that we then learn the lessons from serious case reviews, something that year after year is not done."
More than £100 million will also be pumped into extending two schemes - Frontline and Step Up - which attract the best graduates into social work with bursaries of around £19,000.
An u rgent review of local safeguarding children boards will also be carried out, the serious case review system will be centralised and a "what works centre" will be set up to make sure social workers learn from the best performers.
Education Secretary Nicky Morgan said: "Every single day our most vulnerable children and young people are supported by dedicated, expert social workers - support that changes their lives for the better.
"But in too many towns and cities across the country, children in the most desperate of circumstances are being allowed to slip through the cracks. This simply isn't good enough and every single child failed is a child too many."
Barnardo's chief executive Javed Khan said: "We need to ensure we have the best possible services across the UK to support children and families, especially those who are most vulnerable.
"There must be options, where it is best for the child, to use the expertise of the voluntary sector to complement those already in place. We want to work with local authorities and others in local communities to ensure the best outcomes for children.
"We clearly welcome the opportunity to share our learning from developing and delivering services for children, particularly where we've worked in strategic partnerships with local authorities, to ensure effective solutions can be implemented."
Sunderland City Council leader Paul Watson said: "Sunderland City Council is entirely at one with the Prime Minister in his desire to achieve the best possible outcomes for all our children.
"To this end, we have been working closely with his appointed commissioner, Nick Whitfield, since the July Ofsted report referred to by the PM.
"Together, we have made significant progress as reported to the Secretary of State and the emerging solution is developing well and could be called a trust or be a similar entity.
"We believe that by working closely with the people appointed we will achieve the jointly-desired outcomes in the shortest possible time and in the most effective manner possible."
Alison O'Sullivan, president of the Association of Directors of Children's Services, said: "We recognise that in some areas services are not yet good enough and it is right that we draw on the expertise of the strongest authorities to safely unlock the skills and potential of the practice and corporate leaders working within it and within the wider children's services sector.
"But there is more to improvement than simply changing structures. Parallel to this lies the need for increases in demand to be met with adequate financial resources.
"Even with the closure of many children's centres and youth services we still face a funding shortfall and we risk losing capacity in the system to prevent problems from escalating to a point beyond repair. This must be urgently addressed - we owe it to our children, to our young people and to their families."
Shadow education secretary Lucy Powell said: "It's about time we heard from the Government about the important work that social workers and others do in protecting the most vulnerable children. In five and a half years of their Government, they've said and done very little.
"It's critical that this public service looks at new ways of working and better early intervention programmes to deal with the root causes of rising levels of children and babies in care.
"However, the Government is completely wrong to think that the huge cuts to children's services in most parts of the country on their watch isn't going to have hugely damaging consequences for vulnerable children. This is going to be their legacy: more and more children being failed."