Children in 'inhumane solitary confinement'
At least 40 children have been held in solitary confinement in young offenders institutions in the past year, the Victoria Derbyshire programme has been told.
The UN defines solitary confinement as being held for 22 hours a day without meaningful human contact.
The government said child prisoners were never held in solitary confinement in England and Wales.
Watch the BBC's Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News Channel in the UK.