A Rochester youth jail is among the worst in the country for educating its inmates.
Cookham Wood in Borstal offered an average of just 10 hours of schooling each week to its young offenders in 2011-12, it has been revealed.
It is five hours - or a third less - than the minimum required for its youngsters, aged 15 to 18.
The figures, obtained by the Centre for Social Justice (CSJ) under the Freedom of Information Act, found just one in nine state-run Young Offenders’ Institutions in England are delivering the minimum education required.
The Ministry of Justice said it is planning to “radically overhaul” its youth education programmes.
Edward Boyd, deputy policy director of the CSJ, said he was “very shocked” by the figures.
“What we have at the moment is fundamentally broken, we know education will work to turn their lives around and we are not using it.”
“If you increase the ambition far beyond 15 hours then I think there is a significant chance that re-offending and crime rates would come down.”
“We know that education is the tool that most contributes to reducing re-offending in young people and our only ambition is to give them below average hours of schooling, the government needs to change this.”
The CSJ wants to see the government put education back at the heart of detention - with an overhaul of the system currently in place and the introduction of Secure Colleges.
“It is important that we invest in children inside these institutions and make sure we do all we can to turn their lives around, we need to remember these are kids.”
Mr Boyd added that the lack of current schooling is “unfair” to teenagers’ future prospects.
“It’s also unfair on future victims that are created effectively by us not being able to reduce their levels of re-offending by pouring more of our efforts into their education.”
A Ministry of Justice spokesman said: “We must equip young people in custody with the skills they need to turn their back on crime.
“That is why we are planning to radically overhaul the youth secure estate to provide education with detention, rather than detention with education as an after-thought. Our consultation closed yesterday and we’ll publish our full plans in due course.”