Last month, Lydia Playfoot, a teenager from West Sussex, took her school to the High Court over her right to wear a chastity ring. Miss Playfoot, part of the Silver Ring Thing movement which promotes sexual abstinence among young people, argued that refraining from sex outside marriage, as symbolised by the ring, was central to her religious faith. Banning her from wearing it, especially when the school permitted Sikhs and Muslims to wear their religious symbols, amounted to discrimination.

Miss Playfoot deserves respect. Making such a public stand, when chastity is so unfashionable and those who espouse traditional sexual mores are so widely mocked, demands courage.

But being courageous is not necessarily the same thing as being right.

In spite of appearances, the case turns not so much on rights or political correctness as on categories. How do you categorise a silver ring?

Is it jewellery? If so, it seems odd that the school which, at least according to Ms Playfoot's QC, permits students to wear nose rings, earrings and tongue studs, should ban a student from wearing this particular piece of jewellery. What it symbolises is irrelevant. To discriminate between one piece of jewellery and another seems wholly arbitrary.

Or is it a symbol? If so, it is clearly a 'moral' rather than a 'religious' one. The traditional Christian belief that marriage offers the only suitable context for sex is a moral outworking of basic doctrine, rather than an essential article of faith, still less an essential article that requires symbolic expression. Many chaste, young Christians do not wear silver rings. Conversely, many young non-Christians hold similar views on chastity.

If this is so, perhaps the school is right to ban it. Not doing so would preclude it from drawing too many other moral lines. If Miss Playfoot's beliefs regarding sexual abstinence entitle her to wear a silver ring, do mine (regarding the poor) entitle me to wear a Make Poverty History bracelet, or my friend's (to abortion) to wear a pro-choice pendant? The fact that someone's moral stance is founded on religious beliefs is irrelevant. If a school prohibits the wearing of moral symbols, there is no place for a silver ring.

It seems a mistake, then, to claim Miss Playfoot's 'right' to wear the ring is founded on her Christian faith. If she has a right to wear it, shouldn't her religious beliefs be largely irrelevant?

This topic will be the subject of a future Current Debate on the Theos website.