The decision by the publisher of the Chinese-language edition of National Geographic to sell its latest edition in a transparent plastic packet with a warning about explicit content looks like overreaction. The popular scientific monthly is internationally respected. It is not known for lewd content. However, given the many inconsistent and dubious rulings by our classification board over the years, it is easy to see why the publisher may have felt this a necessary precaution.

The edition contains several computer-generated images of a naked Neanderthal woman. Reasonable people will not be offended by the images - and no ruling had been delivered on them by our Obscene Articles Tribunal.

Freedom of expression is not absolute. This is why every community needs bodies such as the tribunal to uphold its prevailing values or standards. But the tribunal is often seen as delivering arbitrary decisions. For example, it initially ruled two magazines which published explicit photos of pop stars engaged in private sex acts neither indecent nor obscene. The interim classification was overturned on appeal and the photos judged indecent. In another case, the board ruled as indecent harmless articles on sex published by a Chinese University student newspaper and reprints of them by the Ming Pao newspaper. Wisely, the Court of First Instance has overruled the tribunal. Such decisions can create a chilling effect, leading publishers to err on the side of caution rather than risk falling foul of the tribunal - and that is not healthy.