The number of children behind bars has risen above 3,000 for the first time and the Government's youth crime chiefs have warned ministers about the rise in those aged 12 or 13 being locked up.
The Youth Justice Board revealed that there were 10 children aged 12, 75 aged 13 and 177 aged 14 now incarcerated in England and Wales. The number of children in custody under 14 has risen by 47 per cent since last year.
The warnings came as the Home Office revealed to Parliament yesterday that the Prison Service was only 293 places short of full capacity, with the jail population at a record 71,360. Jail chiefs have begun using temporary units and police cells to hold prisoners.
The rise in the number of jailed children, who include 10 girls of 13 and 17 aged 14, comes after David Blunkett, the Home Secretary, invoked legislation last April to allow them to be remanded as well as sentenced into custody.
Lord Warner, chairman of the Youth Justice Board, said yesterday that board members were "uncomfortable" with the numbers of very young children being locked up, particularly on detention and training orders (DTOs), and had expressed its concerns to Mr Blunkett.
Lord Warner said: "I don't think anyone on the board actually feels comfortable with a rising number of 12 and 13-year-olds in custody for other than very grave offences."
He said detaining them could seriously damage their education. "If you put someone into custody for more than four weeks and they are of school age ... the school can remove them from the roll.
"You have the bizarre situation where you could be putting into custody for quite short periods of time school-age kids who are in desperate need of education, who are under- performing educationally, and you have made the whole problem of getting them back into education more difficult."
The youth crime chief called for courts to consider alternatives to custody. He said: "With ... very young children, it shows the whole conflict of purpose between the educational system's role and the criminal justice system's role. That's one of the reasons why we don't think custody is going to work for these very short sentences."
The number of under-18s in custody by May had risen by 10 per cent in a year to a record 3,071, including 2,603 in prisons, 340 in local authority-run secure units and 128 in government-run secure training units.
Lord Warner said he was encouraged that 1,500 children were now subject to Intensive Supervision and Surveillance Programmes, rather than in custody, and called for short sentence DTOs, which require children to spend a few months locked up, to be scrapped.
Detention can traumatise the child and offers little time for effective rehabilitation, the board believes. But Lord Warner said he did not think that no 12-year-olds should be locked up.
"There are a proportion of kids of all ages who are so out of control that without a secure remand for a month you will simply not calm them down." He added that 80 per cent were in custody for the first time and many were "depressed and prone to self-harm".