London audiences had never seen anything quite like it. Fireworks, fountains and live sparrows were just a few of the special effects livening up the premiere of Handel's Rinaldo way back in 1711, prompting the Spectator's critic to compare it sniffily to a Punch and Judy show. Fast forward two hundred years, and you might wonder if there's been any progress. The restrictions of the Royal Albert Hall stage, just an open dais set behind the orchestra, rule out anything too adventurous. So the only water was a blue tarpaulin, and the tweeting birds were digitally remastered. The closest Bruno Ravella's semi-staging came to showbiz razzle-dazzle was a mass exodus on bicycles.

But Robert Carsen's new Glyndebourne production, on which this cut-down version was based, is ingeniously conceived. When updating a tale of warring Christians and Muslims, there are obvious inflammatory pitfalls. Carsen manages to dodge controversy by setting the whole thing in a school - of the old-fashioned compulsory uniform and caning variety. The medieval Crusaders become schoolboys, and the opposing Saracens are teachers. Support comes from a non-singing gang of St Trinian's schoolgirls.

Rinaldo, the proud Christian warrior who sets out to rescue his beloved Almirena from the clutches of the sorceress Armida, is turned into a bullied, luckless schoolboy, and the opera becomes his dream of vengeance and victory. It's a role tailor-made for the feisty pintpot mezzo Sonia Prina, who like the rest of the cast came fresh from the Glyndebourne staging to the Proms. She dominated the stage despite her diminutive size. In the vast Royal Albert Hall her voice fell a little short of the required heft, but she spun the tricky coloratura with vim and accuracy.

One of Carsen's less successful touches is to turn Rinaldo's nemesis Armida into a schoolmistress-cum-dominatrix. Leggy soprano Brenda Rae certainly cast a spell over the male section of the audience in her black rubber catsuit, but her six-of-the-best antics turned what should be a dangerous, malevolent character into a bit of a joke.

That's a criticism which could be extended to other aspects of the production. With much of the score cobbled and bodged together in just two weeks using bits and pieces from earlier works, Rinaldo is not Handel's most dramatically coherent opera. But it still has plenty of fine music - the opera's enormous popularity during Handel's own day attests to that. Yet it seems Carsen couldn't quite trust Handel's music to hold its own, hence the extended pillow fights, the bicycles and the saucy schoolgirls. Many in the audience clearly found the distractions hilarious; I couldn't. Carsen's concept is wickedly clever, but its execution sets a false tone that ultimately betrays the opera.

There could be few complaints about the musical side of the performance though. Almirena was the crystal-voiced Anett Fritsch, who found real emotion in her show-stopping aria Lascia ch'io pianga. In the fast-moving part of Argante, Luca Pisaroni mastered the tricky combination of superb agility and immaculate diction in an attractively warm, rounded baritone. As Eustazio, Tim Mead displayed an unusually powerful countertenor, and as Goffredo, Varduhi Abrahamyan's velvety mezzo settled after a wobbly start .

I have some reservations about the Orchestra of the Age of Enlightenment under Ottavio Dantone. We are used to hearing period orchestras - including the OAE themselves - play Handel with a hard-edged diamantine brilliance, the phrasing clean, each note crisply articulated. Dantone favoured a strangely fuzzy, fudgy sound, rendered even more opaque by the Royal Albert Hall's woolly acoustics. But the enthusiasm of the small band couldn't be faulted. They sounded as fresh at the end as they did the start, with only a few spoiled notes from the natural trumpets to flaw their performance.