Deborah Orr: This young man has been named and shamed enough

Craig Meehan first came to public attention in February, when Shannon Matthews, the nine-year-old daughter of his live-in girlfriend, Karen Matthews, disappeared on the way home from school. Shannon was found 24 days later, physically unharmed, hidden in the drawer of a divan bed in a flat not far from her home in Dewsbury, West Yorkshire.

It did not take nearly so long for the police to discover indecent images of children on Meehan's computer. Those turned up on the day after Shannon went missing, and yesterday Meehan was found guilty on 10 counts of downloading and possessing abusive images. Meehan was sentenced to 20 weeks in prison, and has already spent longer than that on remand. So he was released immediately after sentencing and taken to an undisclosed location.

It is easy to argue that Meehan's sentence is astonishingly short, especially since some of the images found in his possession were level 4 (which means that they feature penetrative sexual activity, and are superseded in obscenity of content only by images classed at level 5). Yet, although he could have been sentenced to a maximum of 10 years in jail for his offences, it is hard to see what might have been gained from this.

The brief sentence suggests that a psychiatrist has concluded that Meehan is not a danger to others. He is just 22 years old, and would no doubt have had to have faced the usual extra restrictions within prisons that sex offenders routinely need for their own protection. Meehan would have spent a long time in prison rubbing shoulders with offenders far more extreme than he is, and it is important to remember that this influence is sometimes dangerous in itself. The kind of rehabilitation that is needed in Meehan's case can be carried out much more successfully outside prison than inside it.

Still, it is unlikely that he will be contemplating his freedom with great relish. His former partner will not be at home to greet him, as she is awaiting trial in November, charged with kidnap, false imprisonment and perverting the course of justice (alongside the relative of Meehan's, Michael Donovan). It is reasonable to assume that Meehan is going to find it difficult ever to regain custody of his child. Because of the high profile of his case, of course, Meehan is going to have an extremely difficult time picking up any of the other threads of his life either.

His conviction will of course demand his inclusion on the sex offenders' register within 72 hours of his release. Further, he has been sentenced to a seven-year sexual offences prevention order, which will entail his monitoring under multi-agency public protection arrangements. These are likely to include visits to psychiatrists and police stations, and sometimes even demand electronic tagging. Failure to comply could result in a five-year prison sentence.

It is darkly serendipitous that Meehan's trial has coincided with the rolling out of the remnants of "Sarah's Law", announced back in the seemingly distant days when John Reid was home secretary, and this week launched in four pilot projects. Initially, there were calls for "Sarah's Law" to be introduced in Britain after the abduction and murder of Sarah Payne by Roy Whiting in 2000. Campaigners, including Sara and Michael Payne, the mother and father of the dead eight-year-old, wanted the names of sex offenders living locally to be released in Britain, as they are in 21 American states under Megan's Law, which was inspired by a similar crime.

Sarah's parents were convinced that such a register would have saved the life of their daughter. Sadly, there is no logical reason why that might have been so.

Nonetheless, after years of debate and wrangling, the Home Office has proposed a system whereby those intimately involved with people they suspect may be on the sex offenders' register can apply to find out if their fears have any grounding in fact. It's a weird sort of compromise, as the very existence of such a suspicion suggests a less than healthy relationship. It will be interesting to see how much the opportunity is actually taken up during the pilot period.

Even this very limited incarnation of the American system has its difficulties. One major concern is that those who have their worries confirmed may find themselves unable to comply with the law and keep their knowledge secret. Vigilantism is still a threat. The campaign to adopt Sarah's Law, taken up so notoriously by the News Of The World, has actually done much to illustrate the law's greatest dangers. When the Sunday tabloid decided to publish the names of convicted offenders released into the community, a wave of violence was famously unleashed, sometimes misdirected, and in two instances prompting suicide.

Although the campaign continues, it is widely accepted that a public register would be inflammatory and too great a threat to public order. There are other arguments against "naming and shaming". It is true, for example, that the practice drives people underground. In Britain 97 per cent of offenders co-operate. In states operating Megan's law, co-operation runs between 80 and 70 per cent. It is true also, as the NSPCC pointed out some years ago, that the system also has the unwelcome habit of allowing offenders to get in touch with each other, like some nonce version of Facebook. But what convinces people more than anything of the dangers of Sarah's Law is the knowledge that an angry mob can mistake a paediatrician for a paedophile, once its blood is up.

The organisation that continues to co-ordinate the campaign for Sarah's Law, however, does boast of one small area in which it has achieved success. It directs those who may be interested to the website of the Government agency CEOP (Child Exploitation and Online Protection service), where the names, mug-shots and a few details of people who have failed to comply with their notification requirements, under the Sexual Offences Act 2003, are displayed with a public appeal for help in their apprehension. The method has been resorted to only on a few occasions, but claims a high success rate.

In reality, this is a complete inversion of the changes in the law that were campaigned for, one in which inclusion on the sex offenders' register, and compliance with the demands of the courts, actually guarantees offenders their anonymity and safety. Only when they stop co-operating do they run the risk of being "named and shamed".

Craig Meehan is likely to want to keep in touch with the authorities every bit as much as they want to keep in touch with him, and to co-operate with them as much as he can. The same can be said of most people in his situation. The present system emerged in part as a way of reassuring the public without resorting to Sarah's Law, and it is a far more fitting and far more practical memorial to a tragically lost little girl than such a rotten idea could ever have been.

d.orr@independent.co.uk