It is not difficult to elicit howls of rage from libertarians over vetting, databases and state nannying. Matthew Parris’s magnificent denunciation in these pages of the new Independent Safeguarding Authority (ISA) and its vast powers to screw up youth groups with compulsory certificates of innocence and £5,000 fines was only the first fleck of the weekend’s foaming outrage. Nor is it difficult to get John Humphrys’ dander up by confronting him at dawn with a moronically droning civil servant repeating empty formulas about “our children”.

However, when the chorus of outrage is joined by Esther Rantzen (“We have to be sensible and I don’t think we are”), the NSPCC (“We are getting a bit too close to the line”), and the President of the Royal College of Paediatrics (“A real danger”), then government faces a perfect storm. By the time you read this Gordon Brown may well have shuffled backwards into consultation and delay, at least until election day.

The critics are quite right. It’s a stupid, excessive scheme, and its big sister the Criminal Records Bureau (CRB) has little to be proud of either. But the criticisms so far have focused on intrusiveness, the insult to all adults, the barrier of fear between generations, the appalling fact that this organisation can use hearsay and unproven allegations, and the obvious point that most child abuse takes place in the home — so the cost of the ISA (£77 million set-up, plus £40 million a year) would be better spent improving social work.

All true. But what puzzles me most about this cockamamie scheme, and many others devised by supposedly intelligent human beings in government, is the extraordinary lack of daily realism. It is as if the word “vulnerable” has a mystical power to suspend all reason. As soon as any group is named vulnerable, no law is deemed too daft. Employment law now states that if you’re not gay, but think that your boss might think you are and dislike you for it, then even if the said boss has never in fact given it a thought and merely resents your idling, you — not he — are in the right. Persecution mania trumps everything: the law now defines racism, disability discrimination and religious insult as anything “perceived” to be such by the victim “or any other person”. It is a paranoid’s and busybody’s charter.

The latest category of vulnerable victims, we learnt on Saturday, is the otherwise healthy, but determined, binge boozer. Despite clear laws against being drunk and disorderly in a public place, the lurching drunk must now, under guidelines issued to the weary 3am copper, be treated as a person “in need of medical assistance”, rather than being shoved in a cell to sleep it off — under half-hourly supervision — and face charges in the morning.

But to return to the ISA, the new vetting-and-barring authority. One of the weirdest aspects of it, as of the CRB, passes unremarked. When droning bureaucrats and drippy ministers wave tiny shrouds and prate about keeping “our children” safe from snatchers and groomers, what do you visualise? Toddlers? Madeleine McCann? Small girls like Holly Wells and Jessica Chapman, bright-faced lads in the under-10 football team? You perhaps forget that a child is legally defined (under the UN Convention) as “any person who is under the age of 18 years”. You can have spent nearly two years earning, married, imprisoned, serving in the Forces or sailing round the world alone and still anybody having contact with you must be vetted, because you are so very Vulnerable.

Once you pass 18 you are on your own. Unless you join another “vulnerable” group. The definition of the v-word, in which condition we must meet only people with government certificates of non- wickedness, is alarmingly loose. Not only the extremely frail, demented or seriously ill are included but anybody who “misuses drugs and/or alcohol” or has “emotional problems”. Gosh. I was very emotional all last week after an extremely sad funeral and I may well have misused some whisky. Yet I cannot be sure that the parcel man who had “contact” with me at the door carried a certificate to prove he would not cause me emotional (“or developmental”) harm while I signed his chit.

OK, I stretch it to the absurd: go back to the solid, worrying matter of the ISA and children. Anyone who has actually met a child might notice that their capacities change with time. The architects of the scheme do not. There is an obvious case for taking close care about who has power over very small children, too young to be warned against sexual dodginess or told that they can safely report to a trusted carer anything that makes them uncomfortable. There is, equally, a need to exclude provenly violent or coercive criminals from getting even biggish teenagers alone in a car or tent. The CRB is meant to do that (even so, it made 1,500 serious errors last year). But as children grow into reasonableness, their safety is best promoted by frankness: by teachers, doctors and mentors who talk straight and listen properly, and by decent street lighting and beat policing. Not by excluding them from ever meeting anyone without a certificate.

None of that growing-up process is reflected in the new regime. Nothing suggests that Philip Pullman reading a story to a class of Year 7s, or a willing mum helping to shepherd GCSE trips to the Natural History Museum, presents less of a peril than handing babies over to an unchecked playgroup volunteer. It assumes that teaching navigation to 30 hulking sea cadets in a Portakabin offers precisely the same opportunity for wickedness as giving a lone three-year-old a lift in your car. Admittedly, if the new rules had set an age limit of say, 12 years old, there would have been a case in the Daily Mail the following week of an evil volunteer driver grabbing a particularly traumatisable 13-year-old footballer’s thigh instead of the gearshift. But hard cases make bad law.

One other thing baffles me. How can it be healthy to keep shovelling off the responsibility of professionals on to layer upon layer of distant agencies? If there were no ISA, or indeed Criminal Records Bureau, it would be incumbent on schools and groups to check several references properly and personally, to exert strong canny judgment and to keep a close eye on their staff, paid and unpaid. But ask anyone in the sector: these days they hardly do.

It’s all in the paperwork. No time to look up.

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