NEW YORK -- Although "A Little Priest" is one of the great Act I finales of all time, rarely is it performed with the kind of grand comic swagger it achieves in John Doyle's irresistibly inventive Broadway revival of "Sweeney Todd, the Demon Barber of Fleet Street."

The interpreters on this occasion are Michael Cerveris -- so powerful in the "Passion" of the 2002 Sondheim Celebration at the Kennedy Center -- and Patti LuPone, playing, respectively, the barber who slices through customers and the meat-shop proprietress who adds them to her menu. What distinguishes their delivery of this gloriously demented song -- a list of the Londoners whom they plan to see cannibalized for profit -- is the meticulousness with which the singers parse and play with Stephen Sondheim's priceless lyrics.

It's tag-team virtuosity, in a production strewn with corpses -- and style. The latest incarnation of a musical many regard as Sondheim's masterpiece is the most radical, and rewarding, revision of the composer's work that Broadway has ever been host to. This statement, unfortunately, is easy to back up. In revival, the Sondheim canon has not fared particularly well on Broadway. (An exception to the usually underwhelming results, the superb "Assassins" staged a year and a half ago at Studio 54 was in fact that 1991 musical's Broadway debut.)

It has been left to Doyle, heretofore a director whose reputation extended no farther than the English Midlands, to show us a surprising way to look at a brilliant piece of chiller theater, set to mournful chords. Downsizing "Sweeney's" largish ensemble to a cast of 10, Doyle squeezes the action onto a compact wooden platform on the stage of the Eugene O'Neill Theater. Realistic scenery has been done away with, and virtually all the props remain stowed on a tower of shelves climbing the back wall. In clever ways, Richard G. Jones's lighting periodically draws the various items into the story.

You might have heard, though, about the musical's most inspired departure. The 10 actors double as the full orchestra, returning to their instruments -- LuPone is on triangle and xylophone and, for a few moments, tuba -- when they're not playing their roles. It makes for an evening of wonderful transparency: The music becomes indivisible from actor and character in a way you almost never experience. The players are in every sense a band, gathered to entertain, sustain a mood and tell a story, to convey every aspect of Sweeney's sorry saga.

Sarah Travis's orchestrations are reductive, yet the haunting and lilting facets of Sondheim's score sound as vibrant as ever. Sweeney's daughter Johanna (Lauren Molina) is a cellist. Sweeney's rival Pirelli (Donna Lynne Champlin) plays the accordion. The slimy Beadle (Alexander Gemignani), who traditionally plays the organ during a second-act duet with the meat-pie lady, Mrs. Lovett, is assigned the keyboard here throughout the production. You wonder sometimes what actors do with themselves backstage, between scenes. There's no backstage here -- no end to being "on." Not even the slash of Sweeney's razor signals a timeout. His victims simply don bloody white coats and return to their clarinets and trumpets.

Doyle's strategy isn't perfect. Metaphors of death are too much with us. Not only is a large black coffin situated center stage, but more preciously, Sweeney's barber chair is also a coffin -- the small white one of a child. The stagy symbolism at times obscures the story. A musical sequence in which Sweeney murders anyone who walks into his shop, which sits atop Mrs. Lovett's grisly House of Mancakes, unfolds foggily; the suspense drains away when you cannot tell whether the killing machine is actually up and running.

On many other scores, however, Doyle runs the table. The idea of starting with the crazed boy Toby (a superb Manoel Felciano) being let out of a straitjacket and into the story is a splendid conceit; we descend into the madness of "Sweeney Todd" with him. And while opera companies often try to stake a claim to "Sweeney Todd," this director makes a solid case for it as musical theater of the purest sort. You can give Sondheim's solos to the world's finest sopranos and most honored baritones, but if an audience cannot make out Sondheim's lyrics -- as so often happens when it's staged as opera -- the production cannot do him justice.

Doyle's version might have actors tooting and strumming, yet it's truly about words, words, words. Which brings us back to Cerveris and LuPone and "A Little Priest." The number here has been rendered definitively. Sweeney and Mrs. Lovett maliciously rhyme the professions of the 19th-century Londoners who'll be sliced and diced and baked into entrees: lawyers, butlers, tinkers, tailors, sailors, vicars, friars. By the time they get to "and we have some shepherd's pie peppered with actual shepherd on top," we've arrived at that magic moment when wit, as a stand-up comic would say, kills.

LuPone is a sterling Mrs. Lovett. It's her best role in years. In a black bob, a la Louise Brooks, and torn fishnet stockings, she cuts a funny, randy figure. She rubs up against Cerveris's Sweeney -- this is a Mrs. Lovett who is ready for the sack -- and you understand completely how wild carnal craving blinds her to Sweeney's less admirable qualities. Cerveris's Sweeney is a homicidal brooder, whose sob-choked murmurings hint at meltdown. Cerveris is an actor who likes the view from the precipice. Although not quite as captivating as some past Sweeneys, he nevertheless exudes a fitting, authoritative creepiness.

Gemignani's Beadle, Diana DiMarzio's Beggar Woman and Champlin's Pirelli are other notable accomplishments. With and without their instruments, they all march thrillingly to Doyle's startling beat.

Sweeney Todd, the Demon Barber of Fleet Street, music and lyrics by Stephen Sondheim, book by Hugh Wheeler. Directed and designed by John Doyle. Lighting, Richard G. Jones; sound, Dan Moses Schreier; wigs and hair, Paul Huntley; musical supervision and orchestrations, Sarah Travis. With Mark Jacoby, John Arbo, Benjamin Magnuson. Approximately 2 hours 30 minutes. At the Eugene O'Neill Theater, 230 W. 49th St., New York. Call 212 239-6200 or visit http://www.telecharge.com .