“We used to call ourselves Bampton Summer Opera… But then we thought we might be had up under the Trade Descriptions Act,” joked Jeremy Gray, welcoming the large audience gathered in St Mary’s Church. Bampton’s opera performances are ordinarily given in the natural open air stage of their beautiful Deanery Garden next door, but when English summer weather drives us under cover, it’s a relief to find the back-up venue warm, comfortable and generally dry (even though the bar corner needed emergency indoor tenting, thieves having recently stripped the lead from the church roof).

There’s always a special sense of relaxed occasion at Bampton: each performance, of just one carefully picked and often rare work, feels like the culmination of months of intense preparation, and yet the whole company glows with the joy of sharing this latest operatic find with the world, creating an atmosphere at once calm, confident and utterly inclusive. This year’s choice, Salieri’s La scuola de’ gelosi, is inspired: a lithe, witty opera about marital (and extra-marital) tensions with an explosively beautiful score, brimming with muscular energy and creative flair from a superb composer. A runaway hit in its day, Bampton’s fresh and skilful production of The School of Jealousy not only makes a great case for reviving another Salieri lost gem (picking up on their exceptional 2015 UK première of La grotta di Trofonio), but also allows us to appreciate its significant influence on Mozart’s Le nozze di Figaro, Don Giovanni and Così fan tutte – all three bear the traces of this masterfully original earlier piece.

Directed and designed by Jeremy Gray, The School of Jealousy flows smoothly from social crisis to emotional crisis before peace and fidelity are finally restored. Gray’s strong young cast attacks the piece with commitment and enthusiasm, whether individually pouting at their spouses in marital discord, or evoking a group of people driven insane by jealousy, licking the prison bars of their asylum (the unlikely setting of the Count’s first clandestine date with Ernestina) and gurning with mad brilliance. Sung in English, with Mazzolà’s libretto wittily translated by Gilly French and Jeremy Gray (there’s plenty of strong rhyme, and even a glorious Fake News joke), the pace and immediacy of this piece never flags.

The sudden change of venue necessarily affected this performance, halving the stage, excluding all but the simplest props, and placing the Orchestra of Bampton Classical Opera, conducted by Anthony Kraus, at a punishing 90º angle for singers trying to connect with their conductor. It was the only feasible place for the orchestra in the space, and the singers coped well with the challenge, but timings could get blurry, especially at the culmination of Salieri’s most complex musical phrases. Regency costumes set the tone of genteel misbehaviour. As the Count, tenor Alessandro Fisher was every inch the Georgette Heyer hero in a bravura performance, naturally commanding and fabulously insouciant, with lyrical tone and surprising philosophical depth behind his agenda of pleasure (in one stupendous aria, the Count gives Blasio a moral lesson on the evils of jealousy, illustrating his points by reference to his own priceless art collection). This Count is a fascinating forerunner to Don Giovanni; he actively discusses his own insatiable desire for women of all kinds, rather than leaving explanations to a lackey. Then, like the Count in The Marriage of Figaro, he finally rekindles true love within his marriage.

As Fisher’s Countess, a poised Rhiannon Llewellyn radiated tense anxiety here, sassy authority there; Llewellyn’s slightly breathy delivery could occasionally diminish her verbal clarity, but the notes her voice can leap up to reach are simply stunning. Generally exhibiting impressive vocal control, Llewellyn was able to deal with momentary problems (sometimes caused by a passing tightness, sometimes by the awkward placing of the orchestra) in her stride. Llewellyn and Fisher made a supremely matched pair in duets, their voices truly complimenting one another in tone and colour.

Kate Howden’s exceptionally clear and luxuriant mezzo, combined with natural and expressive acting, made us wish the servant-girl Carlotta had a larger role. As Lumaca, Carlotta’s fellow servant, Samuel Pantcheff’s liquid baritone and faultless delivery made merry with quickfire passages Rossini might have envied, his sleepy-eyed delivery and comic instinct equally pleasing. Nathalie Chalkley made a composed, articulate Ernestina who gradually slid into the uncontrolled rage of frustrated passion as her husband Blasio pretended to court an imaginary mistress to fire her jealousy; Chalkley’s performance was nicely modulated through her sprightly, smooth soprano and deft control of gesture. Matthew Sprange’s handwringing, furious merchant Blasio was an essay in the Angry Husband which grew in dramatic conviction through the night. With the lightest tenor on stage, Thomas Herford sometimes struggled to give the Lieutenant as much colour as the rest of the cast, despite his innate stage presence. However, the ensemble moments are extraordinary, as Salieri and Mazzolà weave intriguing quintets of sudden pique, pretended disdain and compulsive desire.