Like tens of thousands of pupils, Jeremy Gray is suffering the stress of exam time. But, unlike the majority of GCSE and A-level candidates, Mr Gray, examinations officer at Queen’s college in London’s Harley Street, won’t be able to put his feet up once it’s all over. When the last paper has been sent off to the examination boards later this month, he will go immediately into three weeks’ intensive rehearsals for the festival opera company he runs in what he laughingly refers to as his “spare” time.

“The summer term is my busiest time at school,” says Jeremy Gray, who also teaches art and history of art. “But holidays are handed over entirely to opera.

“School has to take priority in term time. But there’s an ethos here that values what staff do outside their paid employment. I think the school tries to appoint people who do other things and they’re happy to promote the opera as long as it doesn’t interfere with my job.”

Bampton Classical Opera will stage two al fresco productions in July - Mozart’s Cosi Fan Tutte at Westonbirt school in Gloucestershire and a little-known 18th-century masterpiece, Stephen Storace’s The Comedy of Errors, at the Deanery in Bampton, Oxfordshire. It will be only the second British performance of Storace’s work, which has a libretto by Mozart’s best-known collaborator, da Ponte.

The Bampton Opera has no staff other than Mr Gray and his singer-teacher wife, Gilly French, but each summer for the past seven years they have been staging productions of the highest professional standard. Jeremy Gray is administrator, fund-raiser, artistic director and scenery builder, and performs a thousand and one other tasks. But Bampton issues professional contracts to its singers, has always broken even and is gaining a growing reputation in musical circles for its adventurous repertoire and accomplished performances.

“It was never the plan to run an opera company and we had no experience,” says Jeremy Gray. “But Gilly had always wanted to sing Galatea in Handel’s Acis and Galatea and we realised no one was going to ask her to sing it unless we did it ourselves.”

They staged the first event in 1993 with the local arts association in Bampton, Oxfordshire, where they live. “We didn’t have a clue about what we were undertaking,” he says. The owners of the Deanery, a medieval house in the village with wonderful grounds, lent its facilities, and most of the singers were the couple’s friends, “so we didn’t have to pay anyone”. He adds:“People had to bring deckchairs because there was no seating. But everybody seemed to like the atmosphere and wanted us to do it again.”

That first year was, by Jeremy Gray’s own admission,“pretty amateur”. The second year was about “ironing out the problems and getting on top of the enterprise”.

Eight years on, the productions have become thoroughly professional, and Bampton Opera is now a limited company with a respected place in the festival calendar, although people are still bringing deckchairs and picnics because that has become part of the special atmosphere.

Although Jeremy Gray is a gifted pianist, he has never been a professional musician or music teacher. “Music and art went hand in hand for me from infancy, and as a teenager I thought carefully about being a musician. But it seemed so precarious. Now run an opera company I’m glad I didn’t become a musician. It’s so difficult for them to make a living, especially singers. The financial rewards are slight - I know from the paltry amounts we pay them.”

Instead, he studied art at the Courtauld Institute in London, and did a PhD in medieval manuscript illumination. Apart from an interlude in his twenties, when he worked briefly as a designer for the fine chinaware specialist Royal Doulton, he has taught art and art history ever since.

But he believes his break from education was invaluable. “It gave me experience of a different world. There is often a problem with people going straight into teaching after their own education. Anything you can do away from school can only feed into what you do in the classroom,” he says.

He believes teaching and running an opera company complement each other. “As a teacher, you learn to juggle a lot of things and switch quickly from one role to another. That’s held me in good stead. One minute you’re raising money, the next you’re building scenery and then you’re organising rehearsals. Both jobs combine administration and creative activity. Teaching is giving aperformance. You’re putting on a show in the classroom, and if you do it well you’re reflecting creatively on the subject you are teaching. And both involve trying to get the best out of people.”

Much as he enjoys running the opera, Jeremy Gray says he will never give up the day job. “The opera company has grown as big as it can because of funding and time constraints. We don’t have enough money to employ an administrator so we do it ourselves. But it would be crazy to imagine we could make a living from opera. And we wouldn’t want to. Teaching is an extraordinarily broad experience which I wouldn’t want to lose.”

Over the next year he hopes to stage a school opera, as he did successfully at his last school, South Hampstead high, north London. “Bampton ought to be doing education work. It would be an opportunity to bring our professional singers in to help the children.”

Education work would also help to attract more funds, for fundraising is the biggest headache. The Bampton Opera’s policy statement sets great store by making opera accessible and affordable. Tickets this year are pegged at pound;16 - about a third of comparable prices at other open-air opera festivals. This means box office takings cover only a third of the company’s outgoings.

It has not rained during seven years of performances and they have not needed to implement the contingency plan of moving into the local church. But good ticket sales are dependent on good weather. “The economics are touch and go. In a dicey summer, people don’t buy their tickets in advance although they still turn up on the night,” he says.

Consequently, he spends much of his time putting together a patchwork of funding involving a friends scheme, corporate donations and some generous local benefactors. A lottery application is also pending, as is a move to attain charitable status.

But before the curtain goes up on this year’s festival, Jeremy Gray has exams to administer and then rehearsals to get through. “It’s complicated and sometimes tedious,” he says. “But both are richly rewarding. I wouldn’t want to change either.”

Bampton Classical Opera performs Mozart’s Cosi Fan Tutte at Westonbirt school in Gloucestershire on July 15 and 16. Stephen Storace’s The Comedy Of Errors will be performed at the Deanery, Bampton, Oxfordshire, on July 21 and 22. Tickets: 020 7222 1173.