Proms: Squeaky clean: Robert Cowan on a revisionist view of Mozart and Beethoven

The significant 25 years that separate Mozart's 'Great' Mass from Beethoven's Fifth Symphony narrowed to a mere 20 minutes when John Eliot Gardiner launched them both at Wednesday's second Prom. For even in the face of period scholarship, there's no denying a strong personality on the rostrum - and Gardiner's is as strong as any around today. The Orchestre Revolutionnaire et Romantique produces a small, disciplined and unmistakably 'authentic' sonority, with bleached high strings (first and second violins are divided), baleful winds, raucous brass, timpani that sound as if they've come straight off the battlefield and, in the Mozart, the reedy piping of a chamber organ. And Gardiner applies the same sleek, swift and keenly attenuated interpretative formula to both works, leaning to and fro like a dapper marionette and attending to every small detail.

The Mozart Mass employed a first-class line-up of soloists, with Sylvia McNair blending among the winds for a breathtaking account of 'Et incarnatus est'. Her phrasing was sometimes just a touch chichi (especially in the Kyrie), but in other respects hers was the most memorable vocal contribution, with Anne Sofie von Otter, Christoph Pregardien and Alastair Miles providing quality support. It was a 'Great' C minor writ neat and slim, with a small but well-drilled chorus and a tonal cleanliness that sometimes bordered on the clinical.

What would Sir Malcolm have made of it all? And how would Sir Henry have viewed the Beethoven? Certainly the audience was confused: I've never heard so much gabbling between movements. And anyone expecting fate's familiar knock at the door will have been shocked by Gardiner's gatecrashing Allegro con brio, while the actual body of sound produced was far softer then we're used to. This was in fact rather a small-scale revolution, although participants were visibly enthusiastic and the standard of orchestral playing reasonably high.

The Andante was a suave, mobile affair, with fluid phrasing and a seamless top line - not at all the imperious processional that we know from Karajan, Toscanini or Klemperer. Gardiner being Gardiner, there were revelations galore (key manuscript sources having been scoured for long-standing errors), although it was sometimes hard to tell if perceivable differences were due to textual revisions or to personal interpretation. What did register afresh, however, was the all-pervasive presence of the four-note motif, albeit with the Scherzo emerging as a sort of strutting parade, with no hint of the hammering emphases we expected. Gardiner played the repeat, as he did in the finale, and then went on to trigger an accelerating whirlwind of activity for the closing pages. The sum effect was bluff and joyful, a hyperactive and heady half-hour's worth, impetuous yet organised, and usefully mindful of the work's classical roots.

But was I moved, riveted or changed? No. The ideas were interesting and the textures revealing, but Beethoven's carefully tiered climaxes emerged as oddly one-dimensional. I must therefore conclude that I'm incurably infected by Wagner Revisionist Syndrome, and that the big-shouldered, muscular and powerfully weighted version of Beethoven that everyone from Nikisch and Furtwangler to Davis and Masur honours with modern instruments and a refreshing lack of conscience remains, for me at least, unchallenged.