Deputy head Jonathan Hall is on holiday but he is still having to raise his voice to make himself heard with his latest “pupils”. “There’s always a danger that they’ll get up and walk out on me if I get too carried away. They are all adults after all, so I have to watch myself,” he says with a grin.

The class to which he is trying not to raise his voice is a small but dedicated band of amateur actors from Bradford Playhouse and Film Theatre who were rehearsing Hall’s latest play, Buy, which is being staged at the Edinburgh Fringe Festival (Southsive Community Centre, until August 25).

A gritty black comedy which follows the fortunes of four members of staff from the U-Save supermarket, it mixes Hall’s familiar themes of ribald comedy with private pathos. “I like to write about life as I see it and mix in some of my own personal experiences,” he says.

“Quite recently I realised I’d been spending a great deal of my leisure time trawling up and down the aisles of my local supermarket, bumping into trolleys pushed by familiar faces and ordering half a pound of cheddar from the same people every week behind the cheese counter. I began to wonder about them and their lives.”

Buy was premiered at Bradford Playhouse and Film Theatre, the venue where J B Priestley used to try out some of his own plays, including The Good Companions. “Buy is basically a look at people trapped in everyday lives and about having the courage to change direction. It fascinates me, probably because I’ve always been frightened of being at a dead end. I’m always wondering ‘where next?’” Buy is a sharp change of direction from Hall’s previous, award-winning work. Like all good authors, he writes about what he knows. For example, his love of steam trains and railways produced the prize-winning Enthusiastic Men, a black comedy about a group of trainspotters and their inability to express emotions.

However, it is his experience over the past decade as Bradford’s first male infant teacher and now, at the age of 33, the deputy headteacher at Ryecroft First School on the city’s deprived Holmewood estate, that gave him the material and insight to write.

His first play, Nativity, is a classic example. It looks at the relationships between a group of five-year-olds at a Bradford first school as they prepare for their Christmas show. In a Dennis Potter-style reminiscent of Blue Remembered Hills, adults played the five-year-old’s parts and performed at the 1992 Fringe to rave reviews.

“As adults we tend to put up a front in order to be polite. Children, however, don’t. They are often brutally honest, pushy, competitive and very, very cruel. And it makes for great material” But it is not just the playground antics that provide ideas for plays. His play Statements of Attainment, is guaranteed to send a chill down the spines of every primary school teacher south of the border.

“It was a complete nightmare. We all knew it was impossible to teach the amount that was required in a year, but we had no choice,” Hall remembers. “The result, where I worked, was breakdowns, failed marriages and a general air of desperation to get out of teaching fast” The only good thing that came out of what Jonathan describes as the “hellish year” was his play. “It’s my favourite. It’s the one that has come from my real, everyday life. There were so many awful staff meetings, daft Government ideas and silly initiatives going on at the time that I had to get my own back by writing about them.”

With the help of Bradford Playhouse and Film Theatre, Hall took Statements of Attainment to the Edinburgh Fringe and was overawed with the reaction. “Word got round after the first performance. The following night, the performance lasted a good 30-minutes longer because the audience was howling with laughter and wiping away tears. I knew then that I’d hit a nerve.”