Image copyright Jeff J Mitchell Image caption Budget pressures will stretch services for vulnerable children, says the Local Government Association

A funding shortfall in council support for vulnerable children in England will be worse than expected, town hall bosses are warning.

The Local Government Association says a shortfall in children's services budgets will reach £2bn by 2020.

The LGA calculates that the shortfall will be £100m more than was suggested by its previous analysis last October, which had put it at £1.9bn.

The government said its reforms would deliver quality care for all children.

There is already evidence of a funding gap, according to the LGA, with councils having spent £600m more than they had budgeted for in the year 2015-16.

It says the overspend is due to increased demand for children's social care, accompanied by cuts to funding from central government, along with inflation.

The LGA says that population changes mean extra services will be needed, likely to cost an extra £1.1bn each year by 2019-20.

At the same time, reductions to central government grants mean children's services budgets will be down £900m a year, even if councils raise business rates and council taxes to the maximum allowed under government rules, it adds.

The LGA is calling for urgent action to address this widening funding gap and warns that services in many areas are "being pushed to breaking point".

It points to significant increases in demand in recent years:

In 2015-16, more than 170,000 children were subject to child protection investigations, compared with 71,800 10 years earlier

Over the same period, the number of children in formal child protection rose by almost 24,000

Image copyright FotoCuisinette Image caption The LGA warns of a "real and lasting impact upon crucial services"

Tough decisions on how to allocate scarce resources mean early intervention services have been cut and families must reach crisis point before they receive help, warns the LGA.

"There are very few savings left to find without having a real and lasting impact upon crucial services that many children and families across the country desperately rely on," said Richard Watts, chairman of the LGA's Children and Young People Board.

"Early intervention can help to limit the need for children to enter the social care system, lay the groundwork for improved performance at school and even help to ease future pressure on adult social care by reducing the pressure on services for vulnerable adults.

"However, councils are in a difficult situation where they are struggling to invest in this vital early help and support."

A spokeswoman for the Department for Education said: "We want every single child, no matter where they live, to receive the same high quality care and support - and this is exactly what our reforms are set up to deliver.

"We are clear that providing help as early as possible is the most effective way of keeping children safe, and our new What Works Centre for children's social care will ensure social workers across the country are able to learn from best practice."

What Works is a government-led initiative to enable commissioners of public services to access independent evidence across a range of social policy areas.