The prison and probation ombudsman deals with complaints from young offenders institutions and adult prisons but until now did not cover children held in STCs.
The Ministry of Justice (MoJ) has confirmed that the ombudsman’s remit has been extended to include STCs.
Justice Minister Jeremy Wright said: “The prison and probation ombudsman deal with any complaints from young offenders institutions and adult prisons and we are now extending their remit to cover young people detained in secure training centres.
“This will ensure that all those detained in STCs have access to an independent body which can deal with any complaints that arise.”
Campaigners at the Howard League for Penal Reform had issued a legal challenge to the system.
Its chief executive, Frances Crook, said: “I welcome this decision to bring the safeguards afforded to the most vulnerable children on a par with those in prison service accommodation.
“We will now watch closely to see how the new system involving the prisons and probation ombudsman operates, against a backdrop where children in STCs are routinely injured following the use of physical restraint by staff.”
The MoJ denied the change was prompted by the Howard League’s intervention.
STCs, which are run by private firms, are purpose-built for young offenders aged up to 17.