BEHIND GILBERT AND SULLIVAN'S CURTAIN.

Byline: Reed Johnson Staff Writer

Picture this scene: Prima-donna actors indulging themselves with rich cuisine and recreational drugs. Powerful show-biz legends girding their loins for a do-or-die project. A great nation consumed with high living, new technology and entertaining eye candy.

Hollywood, 1999?

Try London, 1884, the setting of ``Topsy-Turvy,'' Mike Leigh's sumptuous and meticulous re-creation of British Imperial culture and the two eminent Victorians who stamped it with indelible panache.

In their gilded heyday, lyricist William Schwenck Gilbert and composer Arthur Sullivan were the leading purveyors of English opera burlesque, that stoutly middle-class art form consisting of faux-naif characters, tongue-twisting verse and preposterous comic plots that gently stood the prevailing social order on its venerable head.

Superficially, Leigh would seem a most unlikely candidate to attempt such a lavishly outfitted period piece. Celebrated for his affectionate but biting depictions of downwardly mobile Brits struggling to survive the Thatcher-Major years, Leigh's forte is contemporary kitchen-sink realism couched in a distinctively personal comic syntax.

``Topsy-Turvy'' starts out deceptively like a hip but more-or-less conventional costume drama, the kind that Britain's Channel 4 cranks out by the yard. Only as the film moves forward, always taking its own sweet time, does the keenness of Leigh's vision, with its purposefully digressive playfulness, fully assert itself.

When we meet them in ``Topsy-Turvy,'' the shrewd, business-minded Gilbert (Jim Broadbent) and the more flamboyant, hedonistic Sullivan (Allan Corduner) have grown rich and famous off their winning formula. Having formed a lucrative alliance with the savvy impresario Richard D'Oyly Carte (Ron Cook), they're the marquee attraction at London's Savoy Theatre and the toast of polite society.

But success has taken its toll, particularly on Sullivan's health and his dreams of musical immortality. Exhausted by the pace of production and fretful that he's frittering away his talent on frivolity, Sullivan tells his partner that they're repeating themselves artistically. Is the British commercial theater's most successful partnership in peril, as the actors are whispering backstage?

After even some risque R&R in Paris fails to lift Sullivan's spirits, Gilbert's demure, understanding wife Kitty (Leslie Manville) drags her husband to a Japanese exhibition. We practically see the light bulb go off above his head. Soon, the company is in rehearsals for ``The Mikado,'' that exquisite spoof of provincial Japanese (read: provincial British) bureaucracy that would become Gilbert and Sullivan's crowning masterpiece.

``Topsy-Turvy'' devotes roughly a third of its two-hour, 40-minute running time to envisioning the creative process behind ``The Mikado.'' Almost a movie within a movie, these revealing, beautifully staged vignettes, filled less with agony and ecstasy than with egotistical sniping and urbane verbal jousting, are surely among the truest sketches of artistic collaboration ever captured on film though they probably presume a greater working knowledge of ``The Mikado'' than they should. Likewise, the extended excerpts from previous Gilbert and Sullivan hits probably will tax some viewers' attention spans.

Pulling talent from his stock company of regular actors, Leigh has assembled a brilliant cast that manages to convey remarkable depths of character with appropriately Victorian understatement.

Sullivan makes a deliciously decadent Sullivan, while Broadbent, practically unrecognizable from his prior role as a working-class loser in ``Life Is Sweet,'' is the perfect counterpoint as the calculating but straight-shooting Gilbert.

Eve Stewart's production design and Dick Pope's cinematography capture London in all its Arts and Crafts/Beaux Arts splendor, right down to the primitive telephones and Vanity Fair caricatures on the walls.

Whatever the century in question, Leigh scrutinizes human behavior with the cool expertise of a butterfly collector, pinning his specimens in sparkling dramatic patterns yet somehow always leaving their humanity intact. Like the best of Gilbert and Sullivan, ``Topsy-Turvy'' cherishes the art of being human, in all its surprising, glorious folly.

The facts

The film: ``Topsy-Turvy'' (R; risque nudity).

The stars: Jim Broadbent, Allan Corduner, Ron Cook, Lesley Manville and Wendy Nottingham.

Behind the scenes: Written and directed by Mike Leigh. Produced by Simon Channing-Williams. Released by USA Films.

Running time: Two hours, 40 minutes.

Playing: AMC Century 14 in Century City.

Our rating: Three stars.