Do you feel a song coming on, Sweeney?
In the classic movie musical 42nd Street, a director tells a chorus girl who's trying to be a lead, "Think of musical comedy, the most glorious words in the English language!" But between the time that film was made in 1933 and its adaptation for the stage in 1980, many modern musicals had stopped being funny. In this new era musicals were not only serious but were also to be taken seriously as a dramatic form.
It was Broadway composer Stephen Sondheim who led the way. His shows variously explored the alienation of bachelorhood (Company, 1970), marital and mental breakdown (Follies, 1971), the Western colonisation of the East (Pacific Overtures, 1976), the revenge impulses of a serial murderer (Sweeney Todd, 1979), the creative and personal demands of being an artist (Sunday in the Park with George, 1984) and presidential killers (Assassins, 1990).
For some the two most glorious (and adventurous) words in the musical theatre lexicon have been Stephen Sondheim, for the past four decades at least. But for many he's still an acquired taste - Andrew Lloyd Webber with The Phantom of the Opera and the French team of Claude-Michel Schönberg and Alain Boublil with Les Misérables have long had the edge in the commercial popularity stakes.
No wonder that the names of Tim Burton and Johnny Depp loom large in the trailer for the film version of Sweeney Todd, while there's only a fleeting credit for its composer and lyricist. Indeed, watching that trailer, you'd be hard pressed to know it is a musical at all: Depp's Sweeney briefly sings a snatch from Epiphany, the big number where he declares "I will have vengeance, I will have salvation!", but the rest of the music heard on the trailer is purely underscoring - little of it comes from the Broadway production.
The fact that Sondheim has been so marginalized is testament to what a minority interest musicals have become. The Oscar-winning success of the film version of Kander and Ebb's Chicago in 2002 led to the hope that they might once again appeal to a mass market, but the screen versions of The Phantom of the Opera, The Producers and even Hairspray have not fulfilled that promise.
People are still suspicious of musicals' artificiality. Despite Sweeney Todd's typically heightened Burton theatricality, the film company promoted it without much reference to its origins in musical theatre. Now there's a backlash, with reports that some film fans feel misled.
Some critics have also wished it were not so heavily musical. On this blog, Andrew Pulver suggested surprise that Burton left the songs in at all: "The Todd story is colourful and gory enough, you'd have thought, without the need for such pedestrian warbling."
So although Sondheim and Burton with their R-rated film have made a musical for grown-ups, the genre's comeback looks more likely to depend on a show that appeals to a youthful, "tween" market: High School Musical. Originally created as a Disney satellite channel movie in 2006, it has already spawned a sequel (whose soundtrack became, astonishingly, the best selling album of any genre last year) and there's a third one on the way. Coming full circle, it has even hit the stage, with a national tour in the US last summer, and the launch of a UK tour last week. Is this the way to go?