Around 170 children between the ages of 12 and 14 may have been wrongly put behind bars in 2007-08, a report published by children’s charity Barnardo’s claimed today.

Government policy states that children aged 14 and younger should only be put into custody if they have committed a ‘grave’ offence, such as murder or rape, or have committed a lesser but still serious offence and are deemed persistent offenders.

The Barnardo’s study, Locking up or giving up?, examined the cases of 214 of the 513 children in this age group who received custodial sentences in 2007-08. It found that more than a third of the cases failed to meet the government’s criteria, suggesting that 170 children may have been wrongly incarcerated that year.

The charity’s chief executive, Martin Narey, said: ‘Barnardo’s is realistic about the reality that some children, even those as young as 12, need to be locked up. But the clear intention of government and parliament is that custody for teenagers as young as this should… be used only as a last resort.

‘This is a tragedy for the young people themselves, it’s a shocking waste of money, and in terms of reducing their offending and doing anything to protect victims it is almost invariably ineffective.’

The study also revealed that just under half the children locked up had been abused; more than a third were living with a known offender; 38% had witnessed violence in their family; 8% had attempted suicide; and the likelihood of being put in custody varied by postcode.

Barnardo’s called for stricter sentencing rules to accurately reflect the intention of government and parliament. It also called for a clear definition of ‘persistent offending’ and an end to custody for children who breach community-based sentences.