Even then, I questioned the advisability of any such presumption, especially in the light of increasing evidence to suggest that the age profile of knife carriers was falling, perhaps to as young as 12.

Now two prominent figures have come up with what appear to be diametrically opposite views as to how knife crime should be tackled. The Archbishop of York wants us to "reach out" to these young people; David Cameron wants "the law coming down on people like a ton of bricks".

These should not necessarily present a simplistic choice. It is, after all, possible both to address the social issues behind knife crime, as Dr John Sentamu urges, and, at the same time, consistently to impose more severe sentences on those found guilty. Different agencies can and should adopt different approaches. Their complementary efforts might produce more constructive results than have so far been achieved.

Much as I admire Dr Sentamu and his philosophy, I cannot disregard my own experience of dealing with crime in inner cities. No one who saw last week's Panorama programme about gangs in Liverpool can find it
easy to share the Archbishop's obviously genuine faith
in humanity.

Gangs of feral youths are "defending their own patch" and "grafting" to make a living. They are not of the same world as those whom the Archbishop meets, even at an event in Birmingham called Bringing Hope. These boys do not share the same day-to-day values as the Archbishop.

They see nothing wrong in being part of a drug supply chain, which explains in part their perceived need to defend their patch. Grafting – street crime to the rest of us – is their preferred way of making money. It offers flexible hours of "work", brings quicker rewards for those with no educational qualifications and is preferable to the more mundane jobs they might face.

Whether or not we can empathise with or accept the stance these young people adopt – and most of us find acceptance impossible – we have to face the facts as they are before we attempt to address the social, educational and economic issues behind this rise in the use of knives. If I paint a bleak picture, it is only a reflection of 30 years' experience in criminal courts.

That brings me on to Mr Cameron's desire to see "a presumption you will go to jail" for carrying a knife. He doesn't quite mean everybody, he says. For example, those bringing their gardening tools home from the shops would not be punished. "This is about kitchen knives being stuffed down the front of tracksuits," explains the man who once wanted us to "hug a hoodie".

There is an important debate to be held about how the criminal justice system deals with a 12-year-old who is arrested at midnight roaming the streets with a knife. If nine times out of 10 there will be nothing beyond a caution, what does that solve? If, instead, there is a prosecution, the inevitable question (assuming, for these purposes only, a conviction) is what penalty should the court impose?

Youth Courts, where most knife offenders would have to be taken, are notoriously a mixture of "proper" courts and social work, but all jumbled into one. While there is a place for both, they should be administered by separate individuals. The nearest the court system comes to that is by making orders putting young offenders under the supervision of social workers.

This is clearly not what Mr Cameron is aiming at. Nor, it would appear, does the Archbishop envisage "reaching out" only by going through a criminal court.

Mr Cameron's approach seems to be very close to mandatory sentences. Those of us who have sentenced offenders of all ages for the widest range of offences know that mandatory minimum sentences rarely, if ever, work. What, for example, would Mr Cameron have as the minimum sentence for a 12-year-old with a concealed knife?

Short sentences generally achieve very little beyond
getting over a message and, in some cases, creating bragging rights. Longer sentences for possession inevitably beg the question of what to do with those who threaten to use a knife, but again do not actually
do so. Longer and longer sentences for younger and younger offenders will create obvious problems, not least the lack of cells for them in the foreseeable future.

The simple truth is that too much prescription will not work. Some young potential offenders can be saved by "reaching out". Others will laugh. A very few may take a caution seriously; most gang members will not. Some convicted defendants will respond to supervision orders; others will respond to very little and need to be taken off the streets for a long time, not just a few weeks.

The offences and the offenders have been neglected for too long. Rather than proposing extreme measures, can we try some joined-up thinking?