What a happy surprise. What an inspiring evening. I went along to the latest of Glyndebourne’s annual community operas – where locals are recruited to perform alongside seasoned professionals, both on stage and in the pit – partly out of curiosity, partly because my old friend Gareth Malone was the chorus master. He has become something of a TV star in the UK, evangelising for communities to get involved with music. Good for him, and on this evidence, good for them. Where I had rather expected something energetic and willing but creatively box-ticking, Knight Crew delivered a genuinely superb theatrical experience. An updating of the Camelot stories (think Excalibur meets West Side Story) based on the popular children’s book by Nicky Singer, King Arthur becomes Art, with Mordred here his brother Mordec, fighting over the soul of the local gang. The first thing to say is that John Fulljames’s staging is magnificent – Es Devlin’s moveable steel cage of a set variously hemming in the teenage warriors, so bursting with misdirected energy, or extending to become platforms along which they strut and fight. And Finn Wright’s projections are so arresting from the outset that the newcomers to opera in the audience didn’t even have time to decide whether they liked the genre or not – they were immediately plunged into the story by the image of a drowning boy ghosting across the set, consuming the characters. Neither does Fulljames overuse what can in lesser hands become a gimmick. Instead, he achieves the most delicate of effects, as when the boys’ mothers yearn for their “lost” children, whose faces appear, staring, over the mothers’ stomachs. Sounds clever-clever? It’s devastating. All the principals throw themselves into their roles. Pascal Charbonneau’s Art is a fascinatingly unstable hero, his epiphany constantly under threat from his own temper – his plangent operatic tenor in marked contrast to Nadim Naaman’s musical theatre-style singing as the beatific Lance (as in Lancelot, get it?). Charbonneau sounds tortured, Naaman’s more shallow vocal production by contrast suggests Lance’s naivety. For the rest, Claire Wild is deeply affecting as Art’s love, Quin, the bass Robert Winslade Anderson by turns louring and literally bouncing with spite as Mordec, and Yvonne Howard alternately tragic and mysterious as the Mother and the strange bag-lady Mrtle. What of the music? What of the community chorus members and orchestra? Impossible to consider them separately on this occasion, as Julian Philips’s moody, propulsive score challenged both so heavily – when all have to encompass Janácekian spirituality and tribalist chanting. The odd lack of polish from the pit notwithstanding, they all pass with flying colours – with boundless commitment, with intensity of expression. It goes beyond learning unfamiliar ways of performing, as does the entire show. By any standards, this is moving, entertaining, and (despite a somewhat over-egged denouement) really rather riveting. If everyone can take enough time away from school and work, it deserves some kind of tour, even a West End transfer. This or Mamma Mia? No competition. Don’t miss the three-part documentary on the project to be broadcast in the UK by the BBC in June.