A private girls’ school in London has been accused of discrimination after it asked a visiting theatre company to cut out references to homosexuality.

St Margaret’s School in Hampstead, which charges £10,000 a year, had invited Black Cat Theatre to give performances as part of a sex education programme for 12 to 15-year-old girls.

The row apparently happened after the first performance on substance abuse and sex showed a boy being raped by another boy.

After one teacher walked out, a school staff member asked the theatre group to cut any subsequent references to homosexuality.

Barry Lillie from Black Cat told the Times Education Supplement that the decision was “morally reprehensible” and would put students in danger.

He said: “It seemed very odd in this day and age. If you are going to broaden children’s minds about sex you have got to talk to them about all different types of sex.

“It is no less important in a girls’ school. There are girls that are gay as well as boys. They can come up against the same prejudices and also catch sexually transmitted diseases.

“We were absolutely astounded that a school would potentially puts it pupils in danger.”

Black Cat said the school had already chosen not to book a performance on gay relationships and was the only school to have asked for references to homosexuality to be removed.

St Margaret’s headteacher Mark Webster told the Evening Standard that staff wanted to be “cautious” about what scenes would be shown later in the day.

“We fail to see how it can be deduced that this request would potentially put the girls in danger’,” Mr Webster said.

“Gay relationships and sex education are part of our school’s personal, social and health education programme.”