A teenager banned from wearing a chastity ring in school told the High Court yesterday that she had been discriminated against for being a Christian.

Lydia Playfoot, 16, a pupil at Millais School in Horsham, West Sussex, said that she wore the ring as a sign of her religious commitment to abstinence from sex until marriage.

But while she was stopped from wearing the ring, the school had allowed Muslim girls to wear headscarves and Sikh students to wear bangles, she argued.

Miss Playfoot claims that her human rights have been violated. If she is successful, she could set a legal precedent over which items can be classed as a cultural expression of religion.

It echoes a row last year in which a British Airways worker, Nadia Eweida, was banned from wearing a cross at work. BA eventually lifted the ban.

In a written statement before the court in Central London, Miss Playfoot stated that the school’s ban had sent a signal to pupils that Christianity was a lesser religion than others.

Paul Diamond, appearing for Miss Playfoot, accused the school authorities of relying on “folk lore” to make their decision. Mr Diamond, who also represented Ms Eweida in the British Airways case, said: “Secular authorities cannot rule on religious truth . . . secular authorities and institutions cannot be arbiters of religious faith.” The school rejected Miss Playfoot’s claims, arguing that the ring was not an integral part of the Christian faith and contravened its uniform policy. The only jewellery pupils at the school were allowed to wear were stud earrings, it claimed.

In a statement of reply, Leon Nettley, the head teacher, said that there had been no discrimination because the ring was not a recognised Christian symbol.

The ring was “just one of several methods of publicising a specific view within the Christian faith”, he wrote. A Muslim girl had been permitted to wear a headscarf, he said, “as it was understood this was considered to be a requirement of her faith” and the school believed that to do otherwise would unlawfully breach her human rights.

The row began two years ago, when Miss Playfoot attended an event by an American Christian movement, the Silver Ring Thing, which promotes abstinence before marriage. She then decided to wear a ring, engraved with a Biblical verse, 1 Thessalonians 4:3-4, which reads: “God wants you to be holy and completely free from sexual immorality.”

Initially, she was allowed to wear her ring but when other friends also got one, she was asked to remove hers on the ground that it contravened the school’s jewellery policy.

Miss Playfoot refused and was made to study separately from her classmates. She was also told that if she persisted in wearing the ring, she would have to leave the school.

She is supported in her challenge by the Lawyers’ Christian Fellowship. Judgment was reserved to a later date.