The Valkyrie, Coliseum, London

Episode Two of Phyllida Lloyd's new staging of Wagner's Ring begins with a blood- curdling scream. Not, I hasten to add, reaction to the news that the Valkyries will be riding west to Glastonbury this summer. Lloyd's leather-clad, windsurfing rock-chicks will be perfectly at home there. No, the scream is Sieglinde awaking from a nightmare in which she finds and loses her soulmate and brother-in-love, Siegmund. And it's a chilling preface to the mother of all storms that also sees the figures of Wotan and his favourite daughter Brünnhilde (they're not due until act two) ensure that Siegmund arrives safely at his destination - and his destiny. Phyllida Lloyd doesn't hang about.

Episode Two of Phyllida Lloyd's new staging of Wagner's Ring begins with a blood- curdling scream. Not, I hasten to add, reaction to the news that the Valkyries will be riding west to Glastonbury this summer. Lloyd's leather-clad, windsurfing rock-chicks will be perfectly at home there. No, the scream is Sieglinde awaking from a nightmare in which she finds and loses her soulmate and brother-in-love, Siegmund. And it's a chilling preface to the mother of all storms that also sees the figures of Wotan and his favourite daughter Brünnhilde (they're not due until act two) ensure that Siegmund arrives safely at his destination - and his destiny. Phyllida Lloyd doesn't hang about.

And so begins the most passionate act in the whole of the Ring. I wish I could say that this is how it sounded here, but somehow or other the fire - literally and metaphorically - was rather late in coming. The conductor Paul Daniel must shoulder most of the blame for this late ignition. In giving his singers room to shape and clarify, he simply lost the impetus. It didn't help that his Siegmund, Par Lindskog, was struggling. He has some good, open notes in his voice, this young man, but joining them up is a problem. Too much crooning, too little phrasing. By contrast, the Sieglinde, Orla Boylan, has come on a treat since last I saw her. The middle of the voice may still need some attention, but the top is great and she's singing now with real feeling.

That feeling is turned to euphoria at the climax of the act, where Lloyd delivers - and how - on Wagner's promise. In the first of several theatrical coups the magic sword, that most sexually explicit of symbols, is drawn not from a tree (there is none) but from between Sieglinde's legs. Nor do the incestuous lovers flee into the forest to frolic. They do it right there and then on the kitchen table.

Over at Valhalla Towers, meanwhile, Wotan is having the usual problems with his ambitious wife Fricka in the corridors of power. In The Rhinegold Lloyd established clear parallels between this relationship and that of the Blairs;politicians, both. Fricka is the power-broker; she wears the trousers. Susan Parry gets that across despite the stridency of her voice, which grows wearisome. But better yet is the way in which Lloyd successfully points up the incompatibility of the "free will" of mortals that Wotan dreams about and the gods - ie, politicians like himself - that govern them. The modern parallels extend to the "Big Brother" use of surveillance, by which means Wotan and the boisterous Brünnhilde can keep tabs on their charges.

Lloyd establishes a real relationship between them. The physical horse-play alone speaks volumes. But here we run into another fatal flaw in the casting of this Ring. Robert Hayward's Wotan is so much at the limit of his capabilities that you doubt his authority and fear for his survival. The voice is pushed, the text too often indistinct, the colour uniform. He is over-parted. There was a time when we may have thought that of Kathleen Broderick's Brünnhilde, but she's more than staying the course. She looks great, she sounds fearless - her battle-cry put the fear of God into me - and she has vulnerability, too. She was heart-rending in the final scene.

The show came into its own here. The rending apart of father and daughter was never in my experience more harrowingly portrayed. This Brünnhilde does not go quietly to the big sleep. She is torn screaming from her father's arms. Orderlies hold her down for the fateful sleeping draft to be administered, which makes Wotan's final gesture of compassion all the more overwhelming. We see a vision of her mentally undressed by a crowd of lusting men and it's more than he can bear. The fire descends, the orchestra at last overwhelms.

To 5 June (020-7632 8300)