At venue three there is Hollywood actor Christian Slater, performing in One Flew Over the Cuckoo’s Nest. At venue 33 there is veteran radio presenter Nicholas Parsons.

And at venue 45 are pupils from Bishop’s Stortford college, in Hertfordshire, performing Richard III.

This is the Edinburgh festival fringe, where unknown school pupils must compete with big names of screen and stage for their share of an audience overwhelmed with choice.

Patrick Ferrante, 18, who plays the title role in Richard III, acknowledges that seeking an audience above adoring parents is a challenge.

“At school, drama can easily become a hobby, not something that’s taken seriously,” he said. “But here, the audience don’t have to come and see you. You need to take time and effort to prepare.”

The youthfulness of the Richard III cast inevitably means that the actors never seem entirely comfortable speaking the verse.

But what lifts the performance above the school hall are a series of genuinely innovative directorial touches. The action is transferred to the 21st century, and modern elements are woven into the script: “here comes a message,” Queen Elizabeth says, as her mobile phone beeps.

Over at venue 65 is Jim Dutton, a former Leicestershire deputy head. He has taken a youth arts group to Edinburgh to perform Once a Catholic, a story of sexual awakening set in a 1950s girls’ Catholic school.

He said: “You can’t rely on mums and dads turning up. The kids really have to compete.”

As with Richard III, portraying characters across the age range can pose difficulties among a youthful cast.

“The most difficult thing for any actor to be is themselves. It’s easier to act a role than to play somebody your own age. So it’s actually very hard for our actors to play fifth-formers,” said Mr Dutton.

No such excuse is available, though, for Jen Nails, an American comedienne, whose one-woman show, Lylice, attempts to recreate life in a US primary.

She romps through a series of stereotypes: the earnest, over-achieving 12-year-old, the hyper-enthusiastic Spanish teacher, and the well-meaning music teacher.

But there is no wit, verve or insight in her characterisations. They reveal no familiarity with the reality of school life.

The publicity material says a Florida teacher has gushed that Lylice made her “think deeply”. This is more revealing as an indictment of the American school system than as a critical appraisal of the show.

But, if at times the festival can seem a haven for underachieving performers, faith is restored by shows such as The Rap Canterbury Tales.

Performed by Baba Brinkman, a 25-year-old Canadian with a satisfying resemblance to chart-topping rap star Eminem, the one-hour performance retells three of Chaucer’s tales for the hip-hop generation.

“I’m sponsored by Miller’s beer,” says one character. “So y’all can call me the Miller.”

His snappy, innovative rhymes retain the spirit of the original text, while also offering a very modern type of poetry.

“Kids can relate to hip-hop,” said Mr Brinkman. “And freestyle rap-battling is very similar to Chaucer’s storytelling competition. I’m an English nerd.

I’m not a gangster. I’ve never shot a gun. But I’m showing that Chaucer can relate to everyday life.”

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