I DON’T say that James Wood’s new opera about everyone’s favourite 12th-century abbess, Hildegard of Bingen, broke the Trade Descriptions Act. But I imagine that many Norfolk and Norwich Festival patrons, lured by the promise of “a spectacle of sound and light”, thought that they were going to get one of those grandiose cathedral son et lumière shows, with the voice of someone like Donald Sinden doing a lugubrious narration while stained-glass windows gently light up.

Oh dear! We had illuminated stained glass and narration of a sort. But what this as-yet-unfinished work chiefly comprised was chunks of Latin screamed out to ferocious swirls of very loud, very electronic and very avant-garde music. “What did you make of that?” I heard one elderly gent ask his companion as they staggered out. “Murder,” she replied. “In the cathedral.”

Indeed. But once you accepted that you were trapped for 90 minutes in a dark nave with a chorus that attacked you from front, side and rear (the brilliantly drilled New London Chamber Choir), six frenetic drummers (Percussion Group the Hague) and an instrumental ensemble (the Critical Band) whose jagged fanfares were bounced electronically a round the nave like aural boomerangs — well, it was all rather ear-popping and thrilling.

And the story? I was afraid you were going to ask that. Hildegard (gloriously sung by Sarah Leonard) enters a monastery as a young girl and starts having astounding visions (cue lots of spooky whispering, building up to frenetic choral explosions). She also develops an obsession with virginity — neatly interpreted by music based on the “pure” harmonic series. The Devil (Omar Ebrahim, suitably rabid) taunts her over fierce percussion onslaughts. Her contemporaries accuse her of idolatry or madness. Nevertheless, she builds her nunnery and dies a virtuous, if noisy, death.

Wood’s music, superbly conducted by Jonathan Stockhammer, owes a fair bit to Xenakis and Messiaen, notably in its ecstatic choral refrains, and virtually nothing to Hildegard’s own chants. But it has tremendous drama too, especially when the performers spread around the cathedral and weave dozens of motifs into jangling cacophony.

What it deserves is a proper staging. What it received here were a few flickers of light and a bit of incense-swinging. Still, Hildegard groupies won’t want to miss it. It’s in London tonight (St John’s, Smith Square), then St David’s Cathedral, Pembrokeshire (May 28), and Salisbury Cathedral (May 31).