Shades of grey are never likely to colour perceptions when it comes to child safety. It is hardly surprising, of course, that there was such astonishment at the news that people who commit sexual offences against young people can be approved to work with children. But who is a sex offender? The 16-year-old boy who has sex with his 15-year-old girlfriend is a very different sex offender from the teacher in England who molested a child of 12 by pulling down his swimming trunks.

Those caught exposing themselves by urinating in a public place are also “sex offenders.” The register is not just a roll call of paeodophiles.

Governments can put in place all the safeguards in the world, but they cannot legislate for human judgement or human error. Some fine decisions will continue to have to be made by civil servants, and the ministers to whom they are responsible, in cases of these kinds. It is not immediately clear whether the central vetting and barring unit planned for Scotland will catch all the culprits, or the right kind of culprits. What is clearer is that it could embroil ministers rather too much for their own political comfort, unless it is to be an arms-length quango.

The fact is that, as Maggie Mellon of Children 1st has pointed out, there are many, many checks; in such a situation, there will therefore be many, many loopholes. It cannot be said too often that children are mainly abused by people in their own families. Knee-jerk emotional reactions to high-profile incidents make bad law.