Teenagers' 'promising futures at risk' from cuts
Further council funding cuts will put thousands of youngsters' "promising futures" at risk, say town hall bosses.
A Local Government Association survey of councils in England, says 90% have cut services for teenagers not in education, employment and training.
Local authorities have seen funding cuts of 40% since 2010, and their responsibility for careers advice and further education has been removed.
The government said the teenage Neet rate was now 64,000 lower than in 2010.
And it highlighted that it is investing £7bn "to fund a place for every 16- to 18-year-old in England who wants one".
Since 2012, local councils in England have no longer had control over careers advice, which has switched to schools.
Local authority-run Connexions services were one of the first areas to be cut under the previous coalition government.
Councils have also lost control of post-16 education and schemes to tackle young people's disengagement.
But the LGA points out that local authorities still have a duty to encourage 16- to 18-year-olds to remain in education, employment or training and ensure there are enough opportunities available locally.
It says local councils are best-placed to oversee support for 14- to 21-year-old Neets because they know what is needed on the ground.
And it warns the advances that it has made could be lost with further cuts ahead.
David Simmonds, chairman of the LGA's Children and Young People Board, said: "The message from local government is clear.
"Cuts without reform risk undoing all of our collective good work, putting thousands of promising futures at risk.
"Councils are uniquely well placed to help young people access the opportunities created by the local employers increasingly frustrated by remote national institutions.
"It is important that we have the powers, levers and funding to fulfil our legal duties to young people.
"The new government has a real opportunity to build on recent successes and meet its ambition of full employment by enabling local partnerships of councils, schools, colleges, jobcentres and employers to locally coordinate a single youth offer.
"It will ensure every young person is either in work or learning."
A survey of 87 local authorities for the LGA also suggests the vast majority (97%) believe services for young people will be put at risk unless councils regain powers over them and general council cuts are avoided.
The Department for Education said: "Thanks to our essential reforms, there are 64,000 fewer 16- to 18-year-olds Neets than there were in 2010.
"We have ended the historic and unfair funding difference between schools and colleges from the 16-19 funding formula, and are maintaining funding rates for 2015-16 so they can plan their future offers for students.
"We are also reforming academic qualifications and vocational education to ensure young people get the knowledge and skills that they need to move into a job, apprenticeship or to continue their education."
The rate of 16- to 18-year-olds who are Neet has tended to fluctuated between 8% and 10% over the past decade, but has been following a downward trend since 2008.