The play, which featured a pupil acting out the role of a father sexually abusing his daughter, shocked teachers, upset parents and left children sobbing and vomiting in distress.
Complaints were made and the two unnamed teachers, who were supervising the 15 and 16-year-olds who wrote and acted in the play, were sacked by the school for gross misconduct.
They are pursuing unfair dismissal claims but suffered a setback when the Employment Appeal Tribunal (EAT) ruled this week that a previous decision in their favour was 'perverse' and that their cases would have to be re-heard.
The teachers taught drama at an unidentified school, one of them as head of the department, and were responsible for supervising GCSE students in the writing, rehearsal, production and performance.
The 'age-inappropriate' material included graphic descriptions of sex, rape, oral sex between father and daughter, child abuse between parents and children, and group sex within a family, EAT judge, Lady Smith, said.
She added: "The principal complaint came from a parent who described not only her own distress, but the distress of others, including a girl who was sobbing after the performance and a boy and one of the actors who were vomiting as a result of their distress."