New figures show that 12 out of 16 YOIs do not meet the HM Inspectorate of Prisons target that young people should spend at least 10 hours a day out of their cell.
Over the month of September 2009, young people were locked up for an average of 16 hours 18 mins in Stoke Heath YOI, meaning they were out of their cells for just 7 hours 42 mins each day.
Also failing to meet the target were Brinsford, Castington, Cookham Wood, Downview, Feltham, Hindley, Huntercombe, Parc, Warren Hill, Werrington and Wetherby.
Across all YOIs young people spent an average of 9 hours 24 mins out of cells.
All secure children's homes (SCHs) and secure training centres (STCs) met the 10-hour target with SCHs averaging 13 hours 18 mins and STCs 13 hours 54 mins.
The situation in YOIs has been labelled "disgraceful" by the Prison Reform Trust.
Penelope Gibbs, director of the trust's campaign to reduce the number of children in custody, said: "We are talking about adolescent boys here. They have a lot of energy and this is just not right." She added that she also believes there is an issue with how long young people get to spend outside of prison buildings in the open air.
Chris Callender, assistant director of the Howard League for Penal Reform, said: "With reoffending rates so high, it is crucial that children are allowed out of their cells to access the services and help they desperately need to turn their lives around."
The statistics came to light following a Parliamentary question tabled by Tory shadow justice minister David Burrowes.
A Prison Service spokesperson said a new recording system has been introduced to improve transparency. "The information from the recording system provided by establishments is used in regular performance reviews," he said.
"The 10-hour time out of cell target is an average requirement. However, the National Offender Management Service and Youth Justice Board have negotiated targets for individual YOIs to adapt to their regimes. Failure to meet these targets is addressed in local management meetings.
"The nature of the YOI population often means that it must be more closely supervised by more staff and in smaller more easily controlled groups," he added. "However, our intention is to provide young offenders with as much purposeful activity as possible."
Staff Ratio Figures
Separate figures released in Parliament show large differences in the ratio of staff to prison places in the youth secure estate.
- The statistics show that ratios in young offender institutions range from 0.5 staff per place at Northallerton (136 staff for 251 places), to 2.1 staff per place at Cookham Wood (228 staff to 108 places)
- Secure training centres are better resourced with between 2.9 staff per place at Rainsbrook to 3.6 staff per place at Medway
- The most intensive support is at secure children's homes, with 5.4 staff per place at Lincolnshire Secure Unit, 4.6 staff per place at Hillside and 4.5 staff per place at Red Bank
