Sarah Payne was abducted and murdered not far from where I now live with my daughter. I can picture children playing in the fields in the evening sunlight. I can imagine Sarah, tired after her day at the beach, running off to her grandparents’ house. I know the area where her body was found, the fields outside my local town. I hope that when my daughter is 8 I will allow her to play in these fields of West Sussex with her friends, unwatched by hovering adults.

So I wondered, as I reread the details of the seven-year-old case yesterday, whether a “Sarah’s law” would make a mother feel reasssured about that. Would Sarah’s law have protected Sarah Payne?

The Home Office is planning to pilot a version of the American Megan’s Law, which allows the names and addresses of known paedophiles to be published. It was introduced in New Jersey in 1994 after the assault and murder of seven-year-old Megan Kanka by a man who lived across the street. In three areas of Britain, including Wansdyke in northeast Somerset, single mothers will be able to check whether a new partner is a paedophile, while parents will be told how many sex offenders live in their street, on their children’s route to school or near playgrounds.

It’s unclear how “near” is near, or how a school route will be defined. As I write, all that the Home Office will confirm is that a story that appeared in Sunday’s News of the World — from which the details above are taken — is accurate, but that it does not know any more than that. This seems a strange way to make policy, given the amount of critical detail that is absent from the News of the World story. You cannot say Sarah’s law is happening unless you know exactly how it is happening. But this, remember, is John Reid’s Home Office, so we shouldn’t be too surprised; government by headline is what he does.

Could there be any policy more senseless than telling parents that serious sex offenders are living in their village or in their street, and then not telling them who they are? Every loner, each unshaven man, anyone who has been “travelling overseas” for more than a fortnight (was he secretly in jail?) will be suspected and targeted. No eccentric will be safe; no newcomer free from suspicion.

And how about that route to school? My route? Yours? The lane your daughter walks down to the bus stop? If your son takes a train that passes through Crawley (where Roy Whiting went to stay with his father after murdering Sarah)? Do they tell you the number of paedophiles in the whole of Crawley, or only the ones living near the station?

None of it would have helped poor Sarah Payne. She lived in Surrey, nowhere near Kingston Gorse on the South Coast where she was abducted. What good would it have done her parents knowing how many paedophiles were in their neighbourhood in Surrey? Even if we had a full Megan’s Law, names and addresses included, I can’t see that it would have helped Sarah; her grandparents, even assuming they checked the register, lived miles away from Whiting’s home in Littlehampton. There will be sex offenders within ten miles of most of us, I imagine.

And as the Wansdyke MP Dan Norris, a former child protection officer, flitted from studio to studio saying how delighted he was to be piloting this, the head of Barnardo’s, Martin Narey, gave warning that the trials would put children in danger, sending sex offenders underground and out of sight of the probation officers who are supposed to monitor them. He claimed Barnardo’s and the NSPCC had been given assurances that the trials would not take place.

And even as I write, the policy is disappearing. The Home Office rings with some “additional guidance”: they are still “in discussion with stakeholders about piloting this model of disclosure”. We are not, parrots the poor mouthpiece forced to spew out Mr Reid’s rubbish, at a “formalised announcement” stage: “We are very much encouraging people not to say that this is what's going to happen.”

There. Despite having spent two days telling people that it was going to happen — and allowing Sarah’s poor mother, who has been campaigning for Sarah’s law for seven years, to believe it was on its way and publicly to welcome it — there, in the puff of a headline, it is gone. Shame, shame, shame on them.

One part of the proposal has survived through Tuesday (for obvious reasons I cannot speak for Wednesday, let alone next week). This is the idea that single mothers should be able to check the background of their new partners, since up to 90 per cent of child sex abuse happens within the family and paedophiles are known to target lone parents. I will be interested to see the detail of that; unless the man has to be asked for his consent to be checked (a tricky conversation to have with a potential new partner), it would enable any community worried about a particular man to check up on him by getting a single mother to call the police and claim she is planning to go out with him. This would introduce a Megan’s Law by the back door.

Well, we shall have to wait and see. “There continues to be discussion within government,” the Home Office is saying. “Already the number of sex offenders in a local police area are detailed in the MAPPA [probation service] annual reports . . .” That is, county by county, and without paedophiles being counted separately, let alone identified. Puff. Sarah’s law is gone.

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