It's the standard music-trivia question and goes along the lines of Donizetti - 55, Verdi - 28, Wagner - 13 and Beethoven - 1: what do the numbers refer to? The answer is, of course, operas; or, in Beethoven's case, opera, for he did, indeed, only pen a single opus in the genre. Coming up with reasons for that state of affairs is mildly interesting - not primarily an operatic composer; had enough difficulty knocking his one opera into a satisfactory shape, etc - though perhaps more interesting is to note that in its final form Beethoven's Fidelio is a resounding success and just as characteristic, individual and powerful as anything he ever wrote.

Which is not to say that, because Fidelio is a masterpiece, it's easy to stage. On the contrary, one of the major stumbling blocks lies in the precise mode employed. Beethoven used the fashionable rescue opera format, which, in Fidelio, centres on an unjustly imprisoned man and a fearlessly dedicated woman (his wife) who sets out, seemingly against great odds, to bring about his freedom. Following on from the aftermath of the French Revolution and written while Vienna lay under siege to Napoleon's armies, there's certainly no denying the topicality, realism and dramatic force of Beethoven's ultimate message. Yet more problematical than the message is the medium, for Beethoven still clothes his "revolutionary" opera in the somewhat stilted form of opera comique, in which the flow of his accumulative musical power of development is constantly stemmed by the intervention of some rather stilted spoken dialogue.

One can easily find reference points for the opera's universality and set it in a Nazi concentration or Siberian labour camp, but, whatever the frame of allusion, it's then far from simple to reconcile the tricky and, it must be admitted, somewhat ludicrous subplot of the jailer's daughter falling in love with the man (who is the woman) who has suddenly appeared from nowhere with a desperate urge to visit the inmate of the lowest dungeons. Again, Beethoven's time throws up no shortage of visual parallels, either for the gruesome or the Gothic underpinnings - the subterranean etchings of Piranesi, for example. Meanwhile, the horrors of a totalitarian regime were equally being mapped out in the work of Beethoven's exact contemporary, the (also deaf) Goya. Neatly weaving his way through the host of possibilities comes dynamic young director Robert Chevara's production for English Touring Opera (above).

Chevara's solution is to mix domestic comedy and heroic melodrama in equal measure, for it is surely apposite that, in Beethoven's conception, devotion, courage and faith are not only loftily presented but form basic humanistic attributes that can emerge from the most banal of everyday situations. The process in which the singspiel-like comedy of the early scenes is gradually left behind for more transcendental territory is also well charted. For Chevara and his designer, Es Devlin, it's all to do with the play of light, as subtle chiaroscuro finally gives way to incandescence. And blazing their way through the musical palette comes the a dedicated and suitably driven ETO cast and orchestra.

English Touring Opera's production of Beethoven's 'Fidelio' arrives at Sadler's Wells at The Peacock Theatre, WC2 (0171-314 8800) 25, 27 Mar, 7.30pm