Proms / Leonore RAH, London

Leonore. It is, of course, the right and proper title for Beethoven's one and only opera. The heart of it beats in its heroine. It is her love, her sacrifice, her courage, her story. She, Leonore, was never destined to change the world. But the world had other ideas. The world wanted to make a man of her. And so she became he - Fidelio.

What's in a title, you may ask? A lot. Beethoven's Leonore was never about the man she pretended to be, but the woman she was: a loving wife seeking justice for her husband in a man's world. A domestic drama with political overtones. Or so it was conceived. Nowadays, the politics count for rather more. Fidelio is perceived as Beethoven's cry for humanity, a universal hymn right up there with the Ninth Symphony. Heilige Kunst ("sacred art") indeed.

So it's good to be reminded of its humble origins, its troubled gestation, to rewind to a time when it was very much work-in-progress - when it was Leonore.

The present restoration - a composite of Beethoven's three versions collated by John Eliot Gardiner and Nicholas McNair - has been "on the road" for some weeks now. Advance reports had greatly raised expectations for Friday's Prom. Gardiner and McNair had replaced the problematic dialogue with a brand-new linking narrative, we were told. Ludwig, the "immortal beloved" himself, was to be our host in the person of Daniel Massey (a logical, if audacious, step up from playing Wilhelm Furtwangler in Ronald Harwood's recent West End hit, Taking Sides). Quite a prospect. In the event, it was not to be.

So where exactly did that leave us? In-the-round and in the lurch, as it happened. Granted the Orchestre Revolutionaire et Romantique (surrounding their conductor in true period style) sounded well at the centre of things, the concentrated drama of the overture, Leonora No 2, spilling over in a clatter of trumpets and drums and gusty period horns. But without dialogue, without narration, Annabel Arden's semi-staging of what was essentially a concert performance of the musical numbers seemed pretty redundant.

In order to "play the hall", to give the entire audience a fair deal - and for no other reason that I could see - singers were required to circumnavigate the orchestra, hopping breathlessly from one raised acting area to another. Voices came and went, depending on when and where you happened to catch them. Poor Rocco (Franz Hawlata) sang his jolly "gold" aria while seemingly engaged in some new Olympic sport (a missed entry at Stage 4, I think it was, cost him a medal).

But hearing Leonore at all is an absorbing, often revelatory, experience. My own view is that, in the main, Leonore is a fascinating but flawed first draft of Fidelio, a masterpiece-in-waiting. Sometimes it's a case of the commonplace phrase lending new and intriguing directions in which to turn - as in Marzelline's first aria (charmingly sung here by Christiane Oelze). At other times, it's a question of simplifying the utterance, harnessing the energy - as in the great love duet of the last act (so much more elaborate in this first version). Some things were always there: Act 1's inspired canon quartet went straight from heart to page. Others, like the extraordinary final section of Florestan's dungeon scene (a startling evocation of delirium which Friday's tenor, Kim Begley, would doubtless have relished), came later, inspirational bolts from the blue.

I sorely missed the tactical shock of "Abscheulicher!", the dramatic recitative preceding Leonore's aria "Komm, Hoffnung", its seismic upheaval of string basses a cry of disgust in the wake of Don Pizarro's entrance aria. Beethoven knew its potency, later sacrificing an undeniably beautiful duet between Leonora and Marzelline (with violin and cello obbligati) in order to maximise its effect. Notwithstanding its absence, Hillevi Martinpelto sang the original (and no less difficult) aria splendidly.

In the final scene (and here's one dramatic coup that Leonore has over Fidelio), Beethoven's populace (Gardiner's Monteverdi Choir) advanced like distant thunder to converge upon the arena from all sides. And yes, it was finally, mightily, exhilarating. But if you had in mind the liberating syncopations that rip through the final chorus of Fidelio, then you'd know that it wasn't enough for Beethoven merely to unlock the shackles, he needed to break free of them. And there's the difference.

EDWARD SECKERSON