OAE / Norrington, Queen Elizabeth Hall, London

Contrary to myth, the output of J S Bach was never wholly forgotten after his death in 1750.

Contrary to myth, the output of J S Bach was never wholly forgotten after his death in 1750. Some of the keyboard music continued to circulate in manuscript; the motets, to be sung in Leipzig, where Mozart heard one. And a belated biography in 1802 sparked new interest. But it was the first performance in a century of the St Matthew Passion, put on in Berlin in 1829 by the 20-year-old Mendelssohn, that really kick-started the great 19th-century Bach revival.

Not that anyone by then had much idea of Bach's performing style. Mendelssohn arrayed a large amateur double choir in front of the orchestra, in which he substituted clarinets for the obsolete oboes d'amore, and accompanied the recitatives on the piano, while peppering the score with his own tempi and expression marks and beefing up the earthquake recitative with full strings.

Indeed, as lovingly recreated from the surviving performance materials by Sir Roger Norrington in this opening concert of the South Bank celebration A Generous Spirit: Mendelssohn the Musician, the young composer's edition evidently inaugurated a Bach sound and tradition that was still going strong in the performances Vaughan Williams used to conduct in Dorking up to the 1950s.

Except that VW would have baulked at cutting a note. Mendelssohn, by contrast, concerned at just how much of this strange and archaic music the Berlin public would stand, cut plenty. Most of the recitatives, he kept, emphasising the narrative strand of the work; and James Gilchrist's histrionic Evangelist was one of the glories of this Queen Elizabeth Hall revival. Likewise, the main choruses were retained, but chorales and reflective arias were removed by the shoal, reducing the work's length by more than an hour.

The result was more rounded in sound and tensely dramatic in impetus than we are now used to, offering a rare contact with a distant world of early-19th-century taste - though it also suggested Mendelssohn's canny judgement in the arias he did retain. Still there, for instance, was the plangent "Erbarme dich, Mein Gott" (even if transposed up from alto to soprano), affectingly delivered by Joanne Lunn. The mezzo-soprano soloist Wilke te Brummelstroete and the Christus of James Rutherford were a little less focused.

The other roles, Peter, Pilate and so on, were taken by members of the choirs, who simply stood up when required and delivered, enhancing the collective feeling of the whole thing - to which a packed house responded with an equally collective satisfaction. The one conspicuous absence from this illuminating experience, which would surely have interested many far beyond the QEH, was any sign of the sound-engineers and microphones of BBC Radio 3 - not the first questionable instance recently of what that service chooses, or chooses not, to record.