Over the course of his nearly 30-year career, director Mike Leigh has become the poet laureate of contemporary working-class Britain, best known for such uncompromised yet deeply humane social dramas as Life Is Sweet, Secrets & Lies, and Naked. For obvious reasons, his sumptuous and hugely entertaining Topsy-Turvy—a period musical-comedy about the making of Gilbert & Sullivan's The Mikado—is a major departure, but it may also be his most personal work to date, an affectionate nod to the theater brimming with sharp insights into the artistic process. At the very least, he must have identified with the creative dilemma facing composer Arthur Sullivan (Allan Corduner), who, as the film opens, feels a similar impulse to strike out into more expansive territory. After a string of popular comic operettas with librettist William Gilbert, including H.M.S. Pinafore and The Pirates Of Penzance, their partnership is threatened by the lukewarm reception to their latest effort, 1884's Princess Ida. But when Gilbert's wife (Lesley Manville) drags him along to a Japanese cultural exhibit, his initial skepticism gradually melts into giddy inspiration as he's wowed by its colorful exoticism. Leigh takes his time with this crucial and fascinating backstory, carefully establishing Gilbert and Sullivan's opposing temperaments while setting the stage—literally and figuratively—for the main event. Then, with invigorating passion and razor-sharp wit, Topsy-Turvy meticulously documents the first production of The Mikado as it progresses from inception to glorious fruition. Given an altogether different milieu to create from scratch, Leigh's typically obsessive attention to detail pays off in both the complicated musical numbers and the tiniest minutiae, including a hilarious running theme on the latest technological gizmos. A great movie could be made out of nothing but Broadbent's bemused reaction shots, but Corduner is every bit his equal in a less showy role. The nearly imperceptible shift in their dynamic together and apart is one of the film's subtler pleasures. For Gilbert & Sullivan, The Mikado arose from a need to break out of what was expected and deliver something new and surprising; that pretty aptly describes what Leigh has accomplished with Topsy-Turvy.