Now is the time to focus efforts on narrowing health inequality

This will include responsibility for commissioning vital services on which families rely, such as health visitors undertaking development checks for babies and toddlers, and Family Nurse Partnerships supporting young first-time mothers.

This new way of working could build on the strengths of local authorities, enabling them to use their knowledge of local needs to target services more effectively. It also gives them the chance to integrate commissioning of services, such as children's centres, parenting support and health visiting, so they extract maximum benefit from working in co-operation.

But the greatest challenge for local authorities is that they will inherit a yawning variation in health outcomes - an inequality gap they will be responsible for closing.

This month, the National Children's Bureau published data on regional variations in the health of children aged under five in a report, Poor Beginnings. Much depends on where children grow up. Those living in poor areas are more likely to suffer from a broad spectrum of health and development problems.

Our analysis of Public Health England's data shows that, for example, if the North West had the same health and development outcomes as the South East, the region would have 1,600 fewer obese fourto five-year olds, 2,500 fewer cases of children admitted to hospital with injuries and 11,000 fewer five-year-olds with tooth decay. There would also be 5,000 extra children achieving a good level of development by the end of reception class.

Within regions we find similar variations: a child in reception class in Barking and Dagenham is over two and a half times more likely to be obese than a child of the same age in Richmond-upon-Thames, just 16 miles away.

But research also indicates these trends are not inevitable for children growing up in deprived areas. Seven local authorities among the 30 most deprived in the country manage to achieve average levels of obesity.

Set this uneven playing field against the funding context for local authorities and the challenge becomes even tougher. A recent investigation by CYP Now, NCB and The Children's Society, found that between 2010 and 2015 funding for local authority early intervention services, including children's centres, had been cut by £1.8bn. And in May the government announced a £200m cut in the public health grant.

NHS England has stated in its Five Year Forward View that the health of millions of children and the sustainability of the NHS depends on a "radical upgrade in prevention and public health". Without proper investment this aspiration may remain out of reach.

The government role is pivotal. In the same way that it has focused attention on narrowing the gap in school performance, the government must now focus on narrowing the gap between different areas of the country in early child health and development. While there is a commitment to improving the narrative across government departments on children's health, I'd like to see this go further with a full children's health strategy.

The government could use its commitment to devolution to build on the approach championed in Greater Manchester, where 10 councils and several local health bodies have come together to work across boundaries, forming a system-wide prevention and early intervention board that is pooling resources and co-ordinating activity.

Public Health England and the Department of Health need to determine why local variations in health occur and how local approaches have been making a difference.

They should also ensure local authorities have the data they need to assess the health and development of young children in their area. That might mean rethinking plans to replace the Early Years Foundation Stage Profile with a narrower "baseline assessment" at the start of school, along with careful oversight of the implementation of the new integrated review check at two, which provides a benchmark of young children's health and development.

It makes sense to transfer children's public health to local authorities. It should lead to far greater joining up of services. The first five years of a child's health are critical to their future development but how they fare on a broad spectrum of health outcomes varies considerably. What is clear is that growing up in a deprived area is a risk factor, not only in itself but because it also contributes to the likelihood of other risk factors occurring.

If we are to stem this inequality, we need a relentless focus by national and local government on narrowing the gap between the best and worst performing areas of the country.

Anna Feuchtwang is chief executive of the National Children's Bureau