One news item that caught the eye today was the report that three councils in Scotland - Stirling, Falkirk and Clackmannan - are planning to ban smokers from adopting or fostering any child under five years old.

The reason given, unsurprisingly, is health grounds and the potential harmful effects of passive smoking: the same justification as supports the ban on smoking in enclosed public places, a highly successful measure, to this observer at least.

Nevertheless there are reasons to question both the wisdom and the legality of any blanket ban. Are we really saying that it is better in all circumstances that a child remain in care than be placed in what is otherwise judged to be a loving home, just because the household includes a smoker or smokers? Is no weight to be given to how heavily or other wise these persons smoke, or where they do it?

As for legality, the unequivocal test is that the welfare of the child is paramount, and that this has to be judged on all the circumstances of the case. And if a decision is taken to judicial review, it is usually a clear ground of challenge that the decision taker has "fettered its discretion", i.e. applied a policy without considering whether to do so is justified in the particular case. on the face of it, the proposed policy would fail on each count.

A further application to all children with certain health problems, such as asthma or heart disease, might seem more reasonable but still potentially open to challenge.

Councils may be worried about potential liability to children in future years, but should they be if a placement decision is taken in good faith and applying the proper tests? If we are concerned with children's welfare, please can we look at it in the round and give each factor its due weight, but no more?