A little girl was murdered here six years ago by a paedophile and it's her name that is being tagged to the campaign, so here it would be called Sarah's Law, at least by the News of the World.
There is definitely a concern with paedophiles, but part of the problem of this obsessive focus on 'stranger danger' is that the vast vast majority of child sex abuse goes on in the immediate family. Now I've heard it suggested that even with this law those convicted of abuse of their own or step-children or nieces and nephews would be exempt because of the risk of identifying the child by exposing the abusers crimes.
Also, if a formerly convicted perv is a danger to the public that danger is only partially mediated by telling everyone what he did. If he is so dangerous as to not be allowed near schools perhaps he is too dangerous to be on the outside altogether? If he is actually safe to be released then any concept of rehabilitation seems under threat from any neighbours and potential employers being able to find out about his past, and atoned for, deeds.
Part of this comes from the recent sentencing of a paedophile. According to the headlines he has been sentenced to five years in prison for the abuse of a child under 5. Unfortunately the Home Secretary stepped in to say that the sentence was too lenient and it all got silly. The sentence was as it is for several reasons, political reasons. He was sentenced to life, which in sex abuse cases is 18 years, he got a third off for pleading guilty (politicians established this), that leaves us with 12 years. Half that and you get the first point at which he is eligible for parole (politicians again). Factor in time served whilst waiting for the courts and you have 5 years. That's the first point at which he is eligible for parole though. The judge in the case said that this guy may never be released from prison.
So child sex abuse cases, independency of the judiciary, criminal law reform and headline-grabbing have been big political footballs here. Knee-jerk legislation on it's way.