A Government Bill is to give local councils unprecedented new powers to opt out of child protection laws, leading children’s charities to warn that vulnerable children could suffer.

The Children and Social Work Bill, which is currently before Parliament, would give ministers the power to exempt local councils from legal duties to children in social care. This includes children under the supervision of social workers and those living in care homes or foster homes.

The change means decades of child protection laws could be ignored by councils who argue they have better – or cheaper - solutions.

40 charities, including Liberty, Women’s Aid and the Howard League for Penal Reform have joined forces to oppose what they call the “dangerous” plans.

Laws that councils could be allowed to opt out of include duties to help young people leaving care, support disabled children and investigate if a child is suffering significant harm.

While some of the council opt-outs would need to be approved by Parliament, others could be granted by the Education Secretary alone, without a parliamentary debate or vote. The exemptions would apply for up to three years, but could then be extended for another three.

The plans, which the Government says are designed to "test different ways of working", could see councils streamlining children’s social care services or outsourcing them to companies who promise to provide the service more efficiently.

It raises the prospect of a big difference in the quality of child protection across the country, with different councils adopting different measures.

And Labour has suggested that the clause will allow councils to outsource child social care to private companies like G4S and Serco in order to cut costs.

Labour peer Lord Watson warned Parliament “there is a serious risk that the links of Serco and G4S could… profit from the care of vulnerable children and their families”.

Martha Spurrier, director of human rights charity Liberty, said: “In one fell swoop, these proposals would let councils opt out of 80 years of children’s care legislation.

“The essential protections those laws enshrine are the product of decades of learning, public consultation, parliamentary scrutiny and, sometimes, the tragic consequences of failure by the state to keep children safe from harm. With no consultation, this Government has decided those protections are dispensable.”

Peter Saunders, founder of the National Association for People Abused in Childhood, said: “There has been no consultation with abuse survivors and no information about which laws are to be tampered with. We have a major inquiry taking place into catastrophic failures in the care of children and yet, incredibly, this Bill will enable the weakening of safeguards and protection.”

A Department for Education spokesperson told The Independent: “We are committed to making sure every child has the best possible start in life and this Bill will help to make this a reality.

“Through our ground-breaking Innovation Programme, we have successfully empowered local authorities to re-think the way they approach their children’s services – the Bill is the next step in this work so they can provide a better service for the families they look after.” Any individual trials would have to be approved by Parliament ‎and will be evaluated.”