The headmaster of a leading British boarding school has threatened to expel pupils if they have romantic relationships. Mr Belfield, 45, a Cambridge maths graduate who became head in 2010, has previously criticised "pathetic" children for being ill and female pupils for wearing short skirts, it has been reported. The school held a sixth-form casino night on Saturday where pupils dressed up, with girls in "little black dresses", according to its website. Mr Belfield was unavailable to talk to Sky News on Wednesday as he was dining with 72 parents in Hong Kong, the school said. Just under two thirds of the pupils at Ruthin are from overseas. In an email to parents regarding relationships, seen by Sky News, he said that all students, staff and parents were aware of his "strict views on behaviour and this is one reason why parents choose Ruthin School". He continued: "Unlike many other schools in the UK, the young people at Ruthin School have exc...