Fewer child offenders should be jailed because prison cannot be expected to solve society's problems, according to Cherie Blair.

She said a "better solution" than jail was needed to deal with the vast majority of young criminals.

We need to find a better solution for the vast majority of young offenders Cherie Blair

The prime minister's wife was speaking to the British Institute of Human Rights at a time of crisis for jails in England and Wales.

There are 10,917 under 21-year-olds in prison in England and Wales - about 16% of the total.

From this number, 2,646 are under 18, a 17% rise in the last 12 months.

Wake-up call

Praising Home Office pilot projects set up to find alternatives to prison, Mrs Blair said: "It strikes me that we can't expect prison to solve the problems of our society.

"I think as far as children in custody are concerned, there are probably always going to be a few children that maybe the solution will have to be custody.

"But clearly what we need to do is find a better solution for the vast majority of young offenders."

Cherie Blair is a part-time judge

Mrs Blair, who is a top barrister and part-time judge, stressed: "People who end up in prison often end up there as a result of a cumulative falling through of various safety nets."

While society has a duty to prevent crime and people have a right to be protected from anti-social behaviour, they needed to be sure that "children are helped to face up to the consequences of their offending behaviour", she said.

Juliet Lyon, director of the Prison Reform Trust, said she hoped Mrs Blair's speech would be heeded.

"Following a 17% rise in the number of children behind bars last year and coming at a point when the Prison Service is bidding to increase its stake in the business of child detention, we hope that Cherie Booth's speech will act as a wake up call that prison is no place for vulnerable children," she said.