Leon Nettley, head teacher of Millais School in Horsham, denies discrimination, saying the ring contravenes the school's rules on wearing jewellery.
"The school is not convinced pupils' rights have been interfered with by the application of the uniform policy," he
told the Brighton-based Argus newspaper.
"The school has a clearly published uniform policy and sets high standards."
The mystery surrounding the end to fictional British boy wizard Harry Potter's saga deepened on Wednesday with a computer hacker posting what he
said were key plot details and a publisher warned the details could be fake.