theartsdesk MOT: Les Misérables, Queen's Theatre

For most people a 25th anniversary is cause for celebration – a party, a dinner, maybe a few speeches. If you are musical theatre phenomenon Les Misérables however, festivities operate on an entirely different scale. London struggles to support two opera houses, yet this anniversary year will be playing host to three separate (and briefly simultaneous) productions of Boublil and Schönberg’s classic show, including an all-star, cast-of-thousands spectacular at the O2.

Skipping over what such excess says about the tastes of London’s theatre-goers, it also says much about the show itself. An all-singing romp through prostitution and penury – is this really still the stuff of great family entertainment?

First things first: the production of Les Misérables currently housed in London’s Queen’s Theatre is far from the twin of the show’s original staging. Lost in the move down the road from the Palace in 2004 was not only stage space but – crucially – a viable orchestra pit.

With the (so-called) orchestra shrunk down to a consumptive 11 players, the musical deficit is supplied by computer, a trade that no amount of slick sound-engineering can really disguise. The joy of Claude-Michel Schönberg’s score is its symphonic quality; the layered motivic writing calls out for a wash of surface strings, and the declamatory climaxes were surely written with a generous team of horns in mind. As it is we make do with a solitary violin (single strings are never a good idea in such an acoustic, particularly when as poorly tuned as this), and lonely solo horn.

The story itself has aged well – a tale of love and revenge played out against a revolutionary backdrop that a global recession has done nothing to undermine. A decades-long conflict between two men may be entertaining enough, but yoke it to a blood-stirring civil cause (complete with fetching uniforms) and a heart-stirring romance (or two) and you have a hit. The stakes here are high; error or just bad luck results in rape, prostitution and death – the emotional ammunition is every bit as deadly as the bullets lodged in the student revolutionaries. When you’re willing to shoot a small, bowl-fringed child (multiple times) on stage, it sends out the message that we’re not in pastel-familiar musical-theatre land anymore, Toto, but something altogether more primary-coloured.

Unlike Phantom or Jersey Boys – essentially domestic shows – Les Misérables is a broader, ensemble piece that demands physical space and scope in order to come into its own. It is the ear-worm chorus numbers –“Look Down”, “Do You Hear the People Sing”, “At the End of the Day” – that give the show its impetus and heart, providing a necessary dramatic frame for the emotional miniatures of the solos. The young cast of the current production clearly understand this, providing one of the most dramatically committed and vocally dynamic ensembles in the West End. There are soloists in other West End shows (Phantom comes to mind) who wouldn’t cut it in the chorus here.

Les Misérables stands or falls with Jean Valjean, the giant of a man whose physical strength is only equalled by his moral rectitude. With a range that could daunt even Mariah Carey (including an entire number, “God Above” sung in a barely audible falsetto), it’s a part that shows no mercy. Understudy Jonathan Williams is astonishing – if Simon Bowman (Valjean regular) can do better I’d be very surprised –  moving from rock-style baritone belting to crooning falsetto with control that is never less than absolute. Matched for vocal power (if not dramatic nuance) by Norm Lewis’s Javert, this is a potent rivalry indeed.

The female leads are currently a face-off between reality TV alumni: Samantha Barks from Andrew Lloyd-Webber’s I’d Do Anything (Eponine) and Lucie Jones of X Factor fame (Cosette). Barks’ voice is pure musical theatre, negotiating extremes of style and range seamlessly, and with all the grubby, gamine charm the part demands. Jones’s pop approach was less successful, frequently breathy and uneven over the tricky upper break where so much of Cosette’s music sits. She is however the only duff note in a cast whose youth is almost as terrifying as their talent.

Surviving changing casts and venues (and even a determinedly unchanging drummer, still in residence with the London show after his 10,000th performance), Les Misérables has become a phenomenon bigger than any single production. When dowdy, provincial 40-something Susan Boyle stumbled into international stardom last year it was with a tune from this show – unlikely proof (if more were needed) of the unpredictable impact of its big melodies and bigger themes. With celebrations just round the corner, here’s wishing London’s original Les Misérables a very happy birthday. Fingers crossed there's a new orchestra pit somewhere among the presents.

• theartsdesk guide to the best musicals in London