With its mysterious title and weighty subject matter, I had expected Vivienne Franzmann’s new play Mogadishu to be a worthy theatrical slog through familiar school-drama territory.

Billed as an exploration of the “vortex of lies” that arises when a white teacher is falsely accused of assault and racism by a pupil, I was geared up for an evening of earnest soul-searching and bleak urban landscapes.

But Ms Franzmann’s fantastic first play, joint winner of the Bruntwood Prize for Playwriting in 2008, turned out to be much more than that.

Despite the subject matter, Ms Franzmann manages to create brilliant and often hilarious extended comedy sequences which interweave well with the hefty “issues” she addresses.

After 12 years working as a teacher, she clearly revels in the humour of young urban pupils - their street-talk and abundant swearing - and their banter is one of the most enjoyable parts of the play.

The pupils also provide some great satire on modern schooling, with a particularly good riff on the unfairness of academic mentoring for CD borderline pupils.

And the humour is not just in the playground. The teacher’s daughter gets some of the best lines as she condemns her mother’s wishy-washy liberal approach to the situation. When her mum refuses to reveal the details of her accuser’s difficult upbringing that prevent her from condemning him completely, her daughter retorts: “Then I guess I’ll have to wait for his misery memoir A Boy Called Shit.”

Teachers in the audience will also enjoy the way the play tackles the issue of cowardly and jaded headteachers (“I never wanted this bloody job, I’m doing it because nobody else will”) and the class difference between staff and pupils. The audience is invited to compare the teacher’s home life, where she sloshes back white wine at her shiny breakfast bar, with the brutality of the school’s bleak “caged” playground.

But it is by no means two hours of laughter. There are frequent dark and uncomfortable scenes tackling self-harm and suicide, the perils of bad parenting, and the politics and fear that can corrupt the attitudes of teachers and their pupils.

The play does occasionally rely on some cliches of school-based drama and becomes melodramatic and shouty in its closing scenes. This is unfortunate, but these are relatively small faults when the play is seen as a whole. A must-see for teachers.