So how does a youth magistrate decide on bail?

Bail is the hardest decision any magistrate ever takes - far harder than verdict or sentence.

Those two decisions have certainty and purpose. But every time you go through the bail process, you're caught in the cross-fire between two constantly warring questions.

On one side, you listen to the Prosecution relate the facts of the alleged offence and (if it's serious) you feel you have to do something to prevent this happening again. On the other side, you stare at the brighteyed 15-year-old face and say to yourself: "Can it really be right to lock this boy up in Feltham for the six or eight weeks until his trial? He hasn't even been found guilty yet."

Above all else, every magistrate dreads granting bail and then hearing that the boy has gone out and committed a serious, violent offence. You read about it happening to magistrates in another court and your stomach hollows out, your knees genuinely go weak.

So does that justify locking everyone up until trial? Of course not. In law, everyone has a right to bail and it can only be withdrawn if we feel the circumstances are exceptional. Under the age of 15, there is no remand into custody at all. So, with a fresh-faced 13-year-old accused, we can deny bail but he will have to be remanded into local authority accommodation.

This usually means a children's home, but it can mean anywhere. The problem is that this might well be back at home, which is the same environment which has failed to control him so far. So frequently we now place an additional condition on the local authority not to place the child with Mrs X or Mr Y. But even a children's home can only report that he has not returned for his curfew, it cannot physically force him to stay in. So if a father/ uncle/brother looks muscular and willing, it is often wiser to grant bail and allow the family to enforce the curfew.

Bail decisions often call for such a juggled solution.

Curfew is only one of the many conditions we have in a bid to keep the boy out of trouble. There are exclusion zones - from estates, postcode areas, the Tube or anywhere which might tempt him into further trouble. We can demand he reports daily to his local police station. Ultimately we can devise anything we feel will prevent re-offending.

Does all this work? Well, he can report to the cop shop and then walk straight out and mug someone. We can curfew him and he can start mugging at different times of the day. You just have to hope it somehow has the desired effect.

To send a 15 or 16-yearold into custody, he not only has to be charged with a "grave crime" (which covers street robbery), we have to believe that the public is in danger of serious harm. This is a high threshold; for instance, it no longer covers domestic burglary. The only remand I ever feel might produce some good arises when the alleged offences are exceptionally serious. In these circumstances, regardless of age, we remand the child into secure accommodation.

These are more than just "locked children's homes". The staff are determined to work with the children and turn them round. There's a downside of course: it costs more than £2,500 per child per week. In the days when the director of social services could veto our choice of secure accommodation, few children were sent there, but the decision is now ours and the Government is funding more secure places.

But I think every youth court magistrate would rather grant bail than see a child go into any children's home. This isn't knee-jerk liberalism: the re-offending rates from young offender institutes are not good. More than 80 per cent of convicted offenders reoffend within the year. So is prison really the place to send an unconvicted offender?