If ever I would leave you,

How could it be in spring-time?

Knowing how in spring I'm bewitched by you so?

If Ever I Would Leave You, by Alan Jay Lerner and Frederic Loewe

© Warner Chappell North America

Now that is what you call a song. It is from Camelot, if you're interested. Used to be on television a lot around Christmas, rarely seen these days. Times have changed. Now, if you want a musical, you get Ben Elton to plunder his record collection for Queen's greatest hits, staple on a plot that wouldn't get a thin-lipped smile from a 12-year-old's English teacher, and away you go. Roll up, roll up for a 50-quid-a-seat karaoke evening. Still packing them in at the Dominion Theatre after almost six years.

Elton replicated the idea with Rod Stewart songs a year later. “Alexei Sayle opened up comedy in this country,” the comedian Jerry Sadowitz said, “and Ben Elton closed it.” He nearly succeeded with musicals, too.

So, apologies if I do not entirely warm to the smash-hit-in-waiting that is Jersey Boys at the Prince Edward Theatre, but I'm a traditionalist. Musicals don't arrive neatly packaged in a CD case at the Virgin Megastore like a series of dots waiting to be joined at a planning meeting by a producer hard-up for ideas and original material. They are new concepts, fresh works. Jersey Boys might have risen above the jukebox-musical formula with its clever take on the story of Frankie Valli and the Four Seasons, and it pitches up from Broadway clutching four Tony Awards, including Best Musical, but it has not introduced one fresh note of music, one lyric that hasn't been heard, to the world. You want a sing-song? That is what the piano in the pub is for. I like a show.

The West End may currently be running with 25 productions that could be classed as musicals, including modern blockbusters such as the incredibly popular Wicked and Avenue Q, but the idea of a revitalisation of the form is very much overplayed. Of that number, six are blockbuster films reworked in the hope that they will already have a receptive audience, five are jukebox musicals using the well-worn hits of popular artists such as Abba or Buddy Holly, five are revivals of old favourites such as The Sound of Music, one is a catalogue show of the works of the composer-lyricist William Finn, another an African take on Mozart, which leaves seven original works, some of which have been running for close on 20 years, such as Phantom of the Opera or Blood Brothers.

Few producers take a chance. Most works have some form of commercial tie-in to ensure success. Spamalot has some new material, most successfully the Andrew Lloyd Webber parody The Song That Goes Like This, but also an incongruous Always Look on the Bright Side of Life, shoehorned in as a simple crowd-pleaser, and it takes its premise from a Monty Python film script that most could recite parrot-fashion. There is no new golden age of the musical, just a load of guys ransacking the past three decades of popular culture for a lucrative hit.

Jersey Boys is more appealing than many jukebox offerings because at least it does not attempt to fashion a coherent plot from a selection of random pop singles (coming soon, The Beatles: the musical, a moving story of Lucy, a little girl who lives on a high hill in a Norwegian wood, with some jewels and a fool, until one day an evil walrus...). Jersey Boys instead tells the story of Frankie Valli and his group from the differing perspectives of the four members, and the songs are presented as if in a concert performance, not as a revelation of a character's inner thoughts or as part of the plot.

This is a step forward from corporations run by Killer Queens being brought down by Galileo and his partner Scaramouche (presumably while doing the fandango), as envisaged by Elton; but not quite the same as a lonely Lorenz Hart drinking himself to death while constructing the waspish To Keep My Love Alive, his final lyric for Richard Rodgers: “Sir Philip played the harp, I cussed the thing/ I crowned him with his harp, to bust the thing/ And now he plays where harps are just the thing/ To keep my love alive.”

Listen to Hart's Manhattan, to his My Funny Valentine or My Romance. Hear the delicious wordplay of songs by Stephen Sondheim - whose Agony, from Into the Woods, sent up the overwrought musical ballad more viciously than Eric Idle ever could - to get a sense of what we are missing. The Four Seasons were a great pop group; so were Abba. This is no attempt to deride them. Nobody is claiming musical theatre is more meaningful as an art form, but it does represent a different journey, which few are now brave enough to attempt.

The phenomenon of the Saturday night talent show is also credited with reawakening an interest in musicals, but has it really? How many of the coach parties that made the trip to see the winsome Connie Fisher as Maria in The Sound of Music would return the next week to see something new at the Donmar Warehouse? These amateur-hour auditions make for wholesome family entertainment on Saturday night - and anything that puts the wonderful Oliver! back on stage, as it will soon be, is no bad thing - but, at heart they have as much to do with our five-minute celebrity culture as any renaissance in musical theatre.

Again, it is a safe bet. The producers want a star who is already a household name, so they create one via the light-entertainment department of the BBC. Good for the box office, good for the ratings, good for a group booking from Kettering. Good for encouraging the new, the challenging, the invention that keeps theatre alive? Not so much. Nobody is arguing against the merit of the classics, but are crowds flocking to hear Rodgers and Hammerstein, or just to gawp at Connie Fisher?

“Jersey Boys is a musical for people who don't like musicals,” says its director, Des McAnuff. Actually, these days just about everything is a musical for people who don't like musicals. It is the people who do like musicals who are screwed. When Channel 4 produced its list of 100 greatest musicals, No13 was an episode of Buffy The Vampire Slayer. Carousel made it to No41. At least it beat The Muppets Take Manhattan, but not by much. Breaking Glass, with Hazel O'Connor, was No95. The Music Man, a sublime, richly complex piece of work by Meredith Willson, featuring songs in march time, waltz time, barbershop, counterpoint melodies and, in the film, a bravura performance from Robert Preston who sings the tongue-twisting Trouble with clarity unsurpassed, did not make it into the list at all. Porgy and Bess was No77, one place above Hedwig and the Angry Inch (no, me neither). An angry mob would have been of more use at that particular moment.

Terry Christian put musicals into television's Room 101 some years ago (which is ironic considering where most people would put Terry Christian), and modern theatre is shot through with, not a love, but a loathing, for the genre. Buffy, you see, is postmodern and ironic and we can sit back and marvel at its cleverness, but an unsophisticated cowboy called Curly suddenly bursting into Oh, What a Beautiful Morning is laughable and kitsch.

Yet Rodgers and Oscar Hammerstein III took a greater chance when calling their most famous composition Oklahoma than any of the West End producers of today take with their corporate rehashes of the pop charts. In 1943, as now, Oklahoma was the embodiment of the hick Southern state, considered conservative and backward by cosmopolitan New York audiences. It would be as marketable as trying to sell a West End musical in 21st-century Britain and titling it Herefordshire.

The best musical theatre - like the best pop music - has brains, heart and creativity. It is exciting, occasionally subversive and daring. What it is becoming is safe, safe, safe. Jersey Boys may be a fun night out, but the modern impresario is obsessed only with something familiar; the days of something peculiar happening in the forum are a memory now.

Jersey Boys is in preview at the Prince Edward Theatre, London W1 (www.prince-edward-theatre.co.uk), and opens on March 18

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