Dance: Dido and Aeneas, Sadler's Wells, London

Watching Keith Warner's production of The Ring on television the other weekend, I found myself wondering what Wagner would have made of all the directorial additions, the visual anachronisms and the character-enlivening jokes. My guess is he would have loved it. Watching Sasha Waltz's production of Dido and Aeneas at Sadler's Wells, the same question presented itself. To what extent would Henry Purcell - once he'd got over the culture shock - have endorsed this spectacular, hardware-heavy treatment of an item he penned for an English girls' school in 1689? With its swimming pool and bungee ropes and naked bodies rolling about, would he even have recognised the story? I barely did.

Waltz, at 44, is the toast of German theatre-art. State-funded to the gills, she was given carte blanche by Berlin State Opera to do something with a repertory classic. Her first stab at a historical work in a career built on experimental dance, this Dido was bound to be unorthodox, with more than a nod towards the abstractionist style pioneered by Pina Bausch, with whom she is often compared. Bausch herself produced a memorable treatment of "Dido's Lament" in an early work, Café Muller, which may be what first drew Waltz to Purcell. Whatever her inspiration, it clearly had nothing to do with loving and understanding baroque opera. Rather than illuminate this gem of a score, a thing of sharp-cut, gleaming clarity, Waltz has buried it in excess packaging: too many people on stage, too many costume changes, too many visual ideas times 10.

You can't deny that some of these ideas are very arresting. During the overture and first chorus, dancers plop, fully dressed, into a long glass tank and squirm about like happy seals, weaving above, below and round each other in dreamy slow motion. On the deck above, a woman pours a cup of tea, then dribbles the remainder into the mouths of the swimmers, who pop to the surface like perch seeking crumbs. The water-level drops, the swimmers exit one by one, and strip to the buff to towel dry, a diversion in itself. But what has this to do with the fated love affair of the Queen of Carthage and her noble warrior? I racked my memory for water references in the first chorus and drew a blank. "When I am laid in earth" this was not.

I resent my mental energy being squandered in this way, looking for significance where there is none to find. Why is that man in black performing a lugubrious solo just now? Why are those bodies rolling in a ball like coupled woodlice? What's with the men in the bungee harness/ the conga-dance/ the woman who pulls a shuttlecock from her bra? After so much of this, you suspend intelligent thought.

Unlike other directors who have inserted dance into opera (Mark Morris, Trisha Brown), Waltz deliberately muddles movers and warblers, giving similar movement motifs to everyone on stage. This makes it hard to tell who's who, though you learn to identify the dancers as the ones who keep their mouths shut. In named roles, Waltz pointedly shadows each vocal soloist with a specific dancer dressed in the same colour - at least, I thought it was one dancer until I read in the programme that in some cases it was two. In any case, it is hard to see how this adds anything to our understanding, either of character or as a way of advancing the narrative. You barely realise that Dido has got it together with Aeneas before you find that he is dead.

When it comes to Dido's famous lament, a mute Dido gesticulating beside the gesticulating singer, what should be moving becomes unwittingly comic. Waltz attires both her Didos in floor-length tresses, and throughout the aria their faces and bodies are obscured by tents of hair from which they struggle to emerge, while the dancer representing Belinda (the singer Belinda unaccountably elsewhere) dives inside one of them, presumably in an effort to save her mistress (or mistresses). I struggled not to laugh.

The real tragedy of this Dido is that the music-making is so superb. Aurore Ugolin sings a gorgeously soft-grained Dido, Deborah York's Belinda is a fluting delight, the baritone Reuben Willcox makes a fine and sturdy Aeneas and all three are fully up to the physical demands of Waltz's direction. As are the gamely up-for-it chorus of Berlin's Vocalconsort - the trained dancers are redundant, truth be told. Just as fascinating as anything on stage is the spectacle of Attilio Cremonesi, a wiry musical director so alert to the subtleties and springiness of Purcell's score that his dynamism, reflected back in the brilliant playing of the Akademie fur Alte Musik, becomes the true star of the show.

jenny.gilbert@independent.co.uk