Was Bach anti-Semitic? The question is guaranteed to make most people jolt, given his reputation as being the most sincerely religious of composers, though it also hovers at the back of my mind whenever I hear the St John Passion.

No one would doubt that the score ranks among the greatest ever composed, nor can one deny that to hear it in performance is to undergo an experience at once harrowing and ennobling. Yet even though St John's Gospel doesn't contain the offensive "blood libel" line incorporated into Mel Gibson's messy film of the Passion, it does present an alarmingly baleful account of Jewish connivance in Christ's death. Bach, meanwhile, sets the utterances of "die Juden" as a series of sibilant fugues that should make us flinch rather than accept them unquestioningly.

Qualms about the work aside, the Barbican's performance, with Nicholas Kraemer conducting the City of London Sinfonia and the Joyful Company of Singers, was pretty momentous, marred only by some miscalculations on the part of the soloists. Tenor Jeremy Ovenden, incisive and committed in the arias, was overly dramatic in his delivery of the Evangelist's narration. Baritone Peter Harvey was his antithesis, tremendous in his characterisation of Peter's guilt and Pilate's dithering, yet disengaged in the arias.

Matthew Hargreaves was a dull Christus, though counter-tenor Robin Blaze and soprano Carolyn Sampson were exceptional. Blaze was hauntingly eloquent in his contemplation of Christ's suffering while Sampson sharply differentiated the soprano's initial confidence - complete with the sweeping statement that she, unlike Peter, would never deny Christ - from the awed figure she becomes after the Crucifixion.

Kraemer was faultless, finding violence as well as pity in the score, as the protracted dissonances that sting like lash strokes gave way to moments of timeless serenity. The choral singing was clear, committed and often flawless in its beauty.