William S. Gilbert and Arthur Sullivan symbolized the popular musical theatre of the 1880s and 90s, as the Gershwins symbolized the 1920s, Rodgers and Hart the 30s and Rodgers and Hammerstein the 40s and 50s. Even today their operettas live on in productions around the world, and now the most unlikely filmmaker possible has made a movie about how G and S created their signature musical comedy, 'The Mikado.'

How it is that the man who wrote and directed the hard, ironic contemporary stories "Life is Sweet," "Naked," and "Secrets and Lies" came to make this period piece may never be known, but Leigh has given us a thoughtful and touching insight into two men who could barely acknowledge each other on the street but found a way to create a lasting portfolio of classic operettas. Their working method was straightforward: Gilbert would write a libretto and Sullivan would set it to music. But when we meet them, Gilbert (Jim Broadbent in a thoughtful, unhurried performance) has been undergoing a long dry spell, writing and rewriting the same story ("Please, not another magic potion plot," says the exasperated Sullivan, who swears he'll never work with Gilbert again).

And Sullivan has his own ambitions, regarding the pieces he's done with Gilbert as just filler while he prepares to write more important stuff. Allan Corduner plays Sullivan with great understanding of this aging rake, a hedonist to the core, taking off for the fleshpots of France and Italy and refusing to set any more of Gilbert's plots to music, even willing to walk out on a lucrative contract with the pair's producer Richard D'Oyly Carte (a beautifully understated performance by Ron Cook) if Gilbert can't come up with something truly different.

And then Gilbert does, when his wife Lucy (Lesley Manville) takes him to an exhibit of Japanese culture and music and opens his eyes and ears to a new theatre possibility. The film intercuts shots of casting, costuming, rehearsing, and then performing "The Mikado" with the backstage gossip and talk and work and arguments that go along with any show. We see the nature of the Gilberts' marriage, and the importance of D'Oyly Carte to the success of the partnership. What we don't see is any kind of conventional 'let's put on the show' structure. The film begins, plays out, and ends on a rather soft note, observing rather than dominating, letting insights come quietly to us through personalities rather than through plot points.

In a way I admire Leigh's reluctance to give us what we've been led to expect through all these years of filmgoing, namely the pumping up of melodrama to a preordained conclusion. But I'm also disappointed in Leigh for abandoning us to the mercies of two men who aren't very insightful and don't want to show their feelings in any case. We wait for the storm to break, but it just blows over. Even the shots of 'The Mikado' in rehearsal and performance lack the wit and delight that do inhabit the work. The singers and actors of the show are letter perfect but without the spark that turns ordinary theatre into fireworks. I admire Leigh for the attempt, but I wish he'd found a way to reveal his people as well as he did in "Life is Sweet."