Town hall chiefs have urged ministers to ring-fence budgets that help stop children joining gangs and committing violent offences amid a surge in knife attacks.
Council bosses said further cuts to youth offending programmes, which are funded by central government, would hamper efforts to turn young people away from crime.
The Local Government Association (LGA), which represents councils, said grants which fund youth offending teams within local authorites have halved from £145m in 2010 to £71.5m in 2018.
Youth offending teams have been on the front line of efforts to tackle so-called “county line” drug supply chains, which often see younger people recruited to “run” drugs between big cities and smaller towns.
The LGA said the recent increase in violent crime should mean that, at the very least, youth crime budgets are maintained at last year’s levels.
Figures suggested youth offending teams had impact. The LGA said there was an 86% drop in first-time offenders over the past decade.
Shortfalls in youth crime budgets have led councils to plug gaps from their own funds, the LGA added.
The association’s Anntoinette Bramble said: “The recent spate of tragic violence across the country underlines the importance of investing in services which protect and support young people, keeping them safe from the lure of gangs or from becoming involved in serious crime.
“Youth offending teams within local authorities have an outstanding record of reducing youth crime and making a real difference to young people’s lives, but they are under huge pressure after seeing their government funding halved.”
A Ministry of Justice spokesperson said: “The number of children entering the criminal justice system for the first time has reduced 85% over the last decade and continues to fall.
“For the last two years we have given the Youth Justice Board £72 million to allow local authorities to provide the best possible services for children and help them turn their backs on crime. The budget for the coming financial year will be set shortly.”