Mary Dejevsky: A better way to fight child sex crime

Sarah's Law allows carers to ask about people with access to their children

All they have in common is that they were young girls who met with a cruel fate and their faces, pictured in happier times, smiled out at us around the same time. In most other respects, their cases are quite different. Yet the laws in their respective countries gave one a better chance of avoiding her fate – and it may not be the one you would think.

Eleven-year old Jaycee Dugard was snatched from her suburban street, and found 18 years later, living in the junk-filled squalor of Phillip Garrido's backyard. By then, she had had two children by her abductor and Phillip Garrido was one of more than 100 registered sex offenders residing in the same down-at-heel postal district in Antioch, California.

Stacey Lawrence was nine and lived in the West Midlands. She set off with her mother's partner for a trip she saw as a treat. Two days later she was found strangled, and maybe sexually molested, in his lorry. Darren Walker was found hanged from a tree nearby.

As it happens, the sad, and separate, fates of these girls highlight the way two laws are working here and in the United States – laws expressly framed to protect children from paedophiles and sex killers.

The legislation known as Megan's Law in the United States differs slightly from state to state. But it is sweeping in its scale and implications. All those convicted of a sex crime must be registered and details of their whereabouts are open to public scrutiny.

Type the words "California" and "sex offender" into any search engine, and you will very soon come across the photos and personal details – last known address, date of birth, etc – of offenders known to live in a particular place. You hardly have to try. This information is required to be in the public domain and it is readily available.

This also helps to explain why there is such a concentration of sex offenders in Antioch. Quite simply, there are not that many other places they can live. In most parts of the United States, housing is segregated by income even more than it is in Britain. People in the plusher districts will object to the resettlement of a sex offender in the neighbourhood; if legitimate protest fails, there is always vigilantism.

Some US states, including California, also have a Jessica's Law, which prevents registered sex offenders from living within a certain distance of a school, park or anywhere else likely to be frequented by children. As most half-desirable areas have such facilities, sex offenders have precious few places to go.

So they gravitate to low-income and poorly-served towns, such as Antioch. These are towns with scant sense of community, where the very American spirit of looking out for others hardly operates – hence the neighbours who turned a deaf ear to the occasional sound of children next door, even though it was common knowledge that Garrido was a convicted rapist.

Another consequence, no less predictable, of the laws named after Megan and Jessica, is the growing tendency of convicted sex offenders to disappear. What possible incentive does anyone have for sticking around as a registered sex offender if there is no possible respite from the crime? Yet compulsory registration and a fixed address are two of the most effective weapons in the armoury of the police against such crime. Megan's Law blows that out of the water.

Here in Britain, the risk that sex offenders will be driven underground is repeatedly cited as the single most compelling reason against introducing legislation on the US model. Yet – understandably – pressure for just such a public "right to know" mounts each time a child's murder or serious sexual assault features in the news. And it is what Sara Payne, mother of eight year-old Sarah – killed by a convicted sex offender – has campaigned for: the right for every parent to know if there is anyone who might pose this sort of threat in the vicinity.

Last year, the Home Office finally gave its blessing to a pilot project that was widely touted as Sarah's Law. And it was convenient for everyone to pretend that this was, in fact, Megan's Law with a British name. It suited the campaigners, because they could claim a victory they were never actually going to win. It suited ministers, because it allowed them to look responsive to public opinion, and it suited a public that succumbs, with tiresome regularity, to fear of paedophiles lurking behind every corner.

But this pilot Sarah's Law was, in fact, very different from Megan's Law, and potentially more effective for that reason. As a rule, it preserves the anonymity of registered offenders, leaving in place the incentive to remain above ground. Their disappearance is what prompts disclosure of identity. Information will be provided about convicted sex offenders in the neighbourhood, but only to those with a reason to ask. There are no police websites, where you can scan, voyeuristically, for paedophiles on your own, or someone else's, patch.

The most innovative, and pertinent, aspect of Sarah's Law, however, allows parents and other carers to ask the police whether someone with access to their children has a child sex conviction. This recognises that abductions, such as that of Jaycee Dugard in California or Sarah Payne here, account for a tiny minority of child sex offences.

The vast majority are committed by members of the child's immediate circle, with fully 80 per cent taking place in the home of the offender or the victim. Mothers who might have concerns about a new partner are among those encouraged to use the service, and in the four areas of the pilot, more than 80 applications for information were received in the first six months alone.

It is true that Stacey Lawrence's killer, although accused of assault by his former wife, would not have shown up in police records – even if Stacey's mother had suspected anything (which she did not). Nor can it be known how often paedophiles seek out lone mothers, with a view to gaining access to their children. But what cannot be disputed is that there will be more cases like Stacey Lawrence's than will have drama of Jaycee Dugard's, and that Sarah's Law is better framed to protect children than Megan's – even if in Stacey's case, tragically, it failed.

m.dejevsky@independent.co.uk