David McVicar's production of Faust relocates Gounod's take on Goethe's great drama to Paris in the years before the Franco-Prussian war. It's a provocative, disturbing piece of music theatre that probes beneath the surface of a work once hugely popular, though now, more often than not, condemned as prurient.

Gounod was nicknamed "the erotic priest" in his lifetime: eliding him with Faust and transposing the opera to the time and place of composition allows McVicar to explore the idea of demonic possession as a metaphor both for the undermining of artistic integrity and for the implosion of a society torn between the antithetical values of hedonism and sanctimony. The drama plays itself out in a no-man's-land between the ritzy profanity of a backstage dressing room and the chilly sanctity of a church, facing each other on opposite sides of Charles Edwards's set. Mephistopheles, like some malign theatrical manager, engineers in turn Faust's descent into druggy sensuality, Marguerite's collapse into insanity and the tatty parades that accompany the departure and return of soldiers to and from the front. What begins as a kind of witty, postmodern game, as McVicar brings in allusions to Gounod's contemporaries Baudelaire, Zola and Manet, tips by the end into something genuinely hellish and malign.

Strong stuff, it's phenomenally well performed, though Orlin Anastassov's Mephistopheles takes a while to settle and is more plausible as a sexual predator than a dangerous demagogue. Angela Gheorghiu has done nothing finer than Marguerite and is horribly convincing in the agonised final scenes. Her Faust, Polish tenor Piotr Beczala, is virile and elegant, seducing us as well as her with some perfectly taken top Cs, and there's a tremendous debut from Canadian baritone Russell Braun as Valentin - a glorious performance in terms of vocal beauty and expressive intensity.

The whole piece is superbly conducted by Mario Benini, too.

· Until September 29. Box office: 020-7304 4000.