Proudly liberal with its pupils when it comes to the arts, the authorities at St Edward’s School have surely reached the limits of what most would deem permissible with a compelling production of Simon Stephens’s Punk Rock.

This 2009 shocker involves activities I had not thought to have heard referred to on a school stage – at least in the presence of teachers. The references come, moreover, in language direct enough to have brought gasps – and the occasional giggle – from some who heard it in the school’s Drama Studio a month ago.

Now the show is off to the Edinburgh Fringe – Teddies’ sixth successive journey north – where its taut action is certain to grip the punters.

The play could hardly be a more fitting choice for performance by sixth formers, focusing as it does on a group of their exact contemporaries, albeit at a state school. We must hope, though, that here is a case where life will never imitate art.

Seventeen-year-old director Emily Smart pulls no punches in her presentation of this disquieting tale, whose impact is only enhanced by cuts that have reduced the running time by half.

In less than an hour, we gain a powerful impression of the dangers of adolescent passions, focusing on those of flaky fantasist William (the watchable Harry Whattoff) for sparky form newcomer Lilly (Sassy Hammersley). But she has eyes only for Nicholas (Fergus Flory).

But until the shocking denouement, it is the activities of the odious bully Bennett (Max Brennan) that most command attention. His principal victim is the nerdish Chadwick (Jack Verschoyle), but few are spared his vicious tongue.

Edinburgh visitors will find Punk Rock at The Space@Niddry Street from Monday till August 11.

CHRISTOPHER GRAY 4/5