I disagree. I don't think that criminalising parents for a smack is in a child's or a parent's best interests. A criminal record could get a parent fired from their job, which would presumably leave them unable to pay their rent / mortgage - child and parents could end up homeless. Ideally parents would not smack kids, but I think in the real world it's better for the kid to put up with a few smacks that don't leave a mark than end up homeless because their parents lose their means of income over a smack by ending up with a criminal record.
Plus children lie and they are too immature to appreciate the consequences of their lies and they are not held accountable under the law for wasting police time or getting the victims of their lies into legal difficulties. It is very expensive to legally defend yourself against a child's lies and you could lose your job while you are being investigated, which could go on for months - if the parent denies it, it would be a child's word against a parent's unless there is an actual 3rd party witness who saw the actual smack. And i doubt the police have the resources to investigate smacks that don't leave a mark.
If a kid wants to accuse their parents of injuring them, I would not be ok with criminalising a parent without some actual evidence - bruises or injury of some kind. Failing any sign of injury, probably better to send the child and parent to family therapy and have the state fund that rather than the state paying for police time and legal costs and legal aid. If therapy does not resolve the situation and the child is still making accusations and wants the parent punished, maybe the child would prefer social services to intervene and take the child into care.
The article says a review of studies by RCPCH found smacking can be damaging to children's behaviour, health and wellbeing. Would have to read up on what they mean by "can be".
It also says children who are smacked are "three times more likely to develop poor mental health and twice as likely to be on the receiving end of serious physical assault and abuse." From the wording I am unclear from their wording if the RCPCH thinks smacking equates to hurting a child and is a form of child abuse - I would want to know what the RCPCH considers as abuse here. I am also unclear what they mean by "three times more likely...and twice as likely" - what does that mean in percentages or actual numbers?
On another note, children are supposed to be learning to become adults living in a stressful world. Children feeling a bit sad, upset, hurt, scared, rejected etc is part of that learning process of becoming an adult - what's wrong with feeling those emotions so long as a child is not experiencing them excessively to the extent they can't function or are physically injured - and there are already rules to say a smack should not leave a mark?