Book of Mormon: The new golden age of the musical So why have critics and commentators spent the past few decades attempting to nail down the coffin lid? There's a clue to be found in Works and Days, a didactic poem written by Hesiod of Ascra in about 700 BC, a good few years before Barbara Dickson joined the cast of Blood Brothers. Hesiod asserted that the Greek world in which he lived was an Age of Iron: wretched, chaotic, debased. Long before this, however, there had been an Age of Gold, in which mortals lived like gods and everything was as upbeat as a first-act curtain number. Unlike the history of art, film or poetry, the history of musical theatre is essentially Hesiodic. Its Golden Age began on March 31 1943, when the curtain rose on Rodgers and Hammerstein's Oklahoma! to reveal not the customary line of chorines, but an old woman hunkering over a butter-churn as an unaccompanied voice sang Oh, What a Beautiful Mornin. From this moment, the old Broadway adage "no girls, no gags, no chance" was abandoned. Musicals were no longer adjustable frames upon which to hang a bunch of songs, they were the 20th-century answer to Wagner's idea of the Gesamtkunstwerk - total works of art offering audiences coherent dramatic narrative, strong characterisation and music integrated with the action: a combination exemplified, in quick succession, by Kiss Me Kate (1948), South Pacific (1949), Guys and Dolls (1950), The King and I (1951) and West Side Story (1957). At a less clearly defined point - somewhere between the death of Oscar Hammerstein in 1959, and the moment in 1968 when the cast of Hair invited the audience up on the stage - the gilt came off the gingerbread. We are now, so the narrative goes, in an Iron Age dominated by the jukebox musical - Viva Forever!, Thriller - Live, We Will Rock You - in which someone's overfamiliar back-catalogue is heated up and beaten into something faintly resembling a plot. Until there's a Dorothy Squires one in which she attempts to win back the affections of Roger Moore by belting I, the Chosen One through his letterbox at 3am, this kind of show will remain mostly lifeless - and best explained by that moment in Hello, Dolly! when the heroine tells Horace Vandergelder to go back home and snuggle up to his cash register: "It's a little lumpy," she snarls, "but it rings!" A Chorus Line There are many such devices in the West End now, but jukebox mechanics will not explain the workings of Once, or Sam Mendes's forthcoming toe-and-tune take on Charlie and the Chocolate Factory. Neither will they account for the imminent arrival of The Scottsboro Boys, Kander and Ebb's show about nine black teenagers on trial for rape in Thirties Alabama. Try building that narrative from old David Essex numbers. If this is an Age of Iron, then there are plenty of golden tickets to be had - and there is still a need for the cohesive, all-embracing art that first glowed in Oklahoma! My professional involvement with musicals goes back two decades, when I sold ice cream in front of Andrew Lloyd Webber and Don Black's Tell Me on a Sunday. From behind my tray at the back of the circle of the Manchester Opera House, I learned a lot about musical theatre. I learned that in 1989, Hair still had the power to shock - judging, at least, by the faces of the Bulgarian Olympic weightlifting team, when they emerged ashen-faced at the interval and asked to go back to their hotel. I learned, too, that there is an art to dying a death in a bad musical - and that it is a noble one. I was taught this lesson by Joe Brown - the NME's Top Vocal Personality of 1962 and the original leading man of Charlie Girl - as he gave his all to the 61 people who had turned up to see him play a second-hand car dealer in a "cockney comedy musical" called One Careful Owner. The company manager was so desperate to fill the theatre that handfuls of complimentary tickets were disgorged upon the staff. I gave them to my friends, who were not madly enthusiastic. In order to convince them that One Careful Owner would be a hilariously ironic experience, I created a series of Joe Brown stick puppets out of drinking straws. After the show we went to a bar and began our own impromptu re-enactment of the show, with particular emphasis on a number called You Can Always Tell a Feller by his Car, a meditation on the relationship between the vehicles and the sexual proclivities of men of different European nations. "Old Hermann," the song went, "likes the fräuleins who say ja." At this point, Brown himself walked in, noticed the bobbing chorus of paper doppelgangers, and said, brightly, "Is that merchandise for the show? Great. His cheerful professionalism made me want to die of shame. Merrily We Roll Along After that, my attitude changed. When a show about the music hall star Marie Lloyd made landfall in the same venue, business was so bad that the theatre closed the upper tier of seating. The piece was named Up in the Gallery, after Lloyd's most durable number. When the star, Adrienne Posta, gazed wistfully up at the rows of unfilled seats and declared, "there he is! Can't you see/ Waving his handkerchief?" it was curiously moving. I sensed something similar in the air at Foxwood's Theatre on 42nd Street during the notoriously disaster-prone Spider-Man musical. In January 2011 the show had yet to be enmeshed in the unseemly web of litigation in which it now wriggles, but the producers were refusing to admit the critics, actors were being admitted to hospital by onstage accidents, the book was a mess and Bono's songs stank. The stagecraft, however, was extraordinary. A street full of tiny mechanical New York cabs chugged across the back wall of the stage, giving the impression that the theatre had been upended and we were gazing down from the roof of a skyscraper. Multiple actors in red-and-blue Lycra swung and scuttled and swooped around the auditorium, creating the illusion of a single superhero in transit across the theatre. It was a species of catastrophe, but it was also a thing of wonder. A Hindenburg disaster from which everyone walked out alive. In London right now the hottest ticket for what was once called the legitimate stage is Peter Morgan's The Audience, a work of such complacency that it makes Dreamboats and Petticoats look like the Marat/Sade. This is jukebox playwriting, with British prime ministers instead of Radio 2 standards, and it is so egregiously smug that with any luck it will trigger the writing of the next Look Back in Anger. At the other end of Rupert Street, however, is the sharpest and most troubling play in town. The Book of Mormon is about faith, reason, cultural imperialism, moral self-regard and the Problem of Evil. A collaboration between the creators of South Park and the writer of Avenue Q, it sits in a recognisable Broadway tradition. Like South Pacific and The King and I, its leads are Westerners out of their moral and political comfort zone. Unlike those shows, however, it has another, more anxious preoccupation - the death of musical theatre. Dreamboats and Petticoats The Book of Mormon is acutely aware that the obituary of the musical has already been written. Its grinning paean to sexual and emotional repression - called Turn it Off - is an acknowledgement that its kind of theatre is often dismissed as glib and shallow. Its Ugandan village scenes exist to demonstrate the absurdity of using show tunes to make meaningful comment on African poverty, child soldiering or the Aids epidemic. Its sense of the musical as a worked-out, decadent, decomposing art is, perversely, the source of its monstrous vitality. On this evidence, I hope the musical stays dead. May it dance on its own grave forever. The Book of Mormon opens today at the Prince of Wales Theatre, London W1 (0844 482 5110; bookofmormonlondon.com); Once is in previews at the Phoenix Theatre, London, WC2 (0844 871 7629; oncemusical.co.uk) Get tickets to the Book of Mormon from Telegraph Box Office >