The Bach Choir / Philharmonia / Hunt, Royal Festival Hall, London

Beethoven's oratorio Christ on the Mount of Olives remains one of the great mysteries of his output. This was his first substantial religious work, composed in 1803 just at the point when he realised he was going deaf, and he evidently set great store by it - sketching the cantata-like structure in great detail and revising it twice. Yet if the 19th century was happy to accept the work on its pious intentions, recent generations have found it curiously uncharacteristic on the rare occasions when it is performed at all.

Was its theme of submission to God's will simply too self-abasing to inspire a composer who would shortly "seize Fate by the throat" and bounce back with the Eroica Symphony? In seeking to get to grips with it, The Bach Choir and Philharmonia under Donald Hunt at least ensured the work would have a sizeable audience by following it with Mozart's Requiem and preceding it - rather more oddly - with Brahms's Alto Rhapsody.

Oddly, because it is difficult to imagine that this most explicit expression of Brahms's loneliness, with its shuddering introduction and anguished chromaticism, can often have figured as a concert opener. But this would be to reckon without that commanding mezzo- soprano Catherine Wyn-Rogers, whose immaculate projection of Goethe's text and sonorous phrasing generated a mood of intense concentration. So the Beethoven got under way in favourable circumstances, its marmoreal orchestral introduction and agitated opening scena for Christ unfolding with some force, even if that lyric tenor James Gilchrist sounded (understandably) stressed at times by Beethoven's cruelly high writing.

But then in comes a comforting soprano Seraph, like some cheerful visitant from Haydn's Creation, sung with burnished brightness by Carolyn Sampson, but utterly at odds with the ominousness of what is, after all, supposed to be the eve of the Crucifixion. The arrest of Christ and the protests of Peter, sung by the bass Michael George, restore some drama, but this is again undercut by a triumphant march and chorus of Angels at the end. Hunt and his forces gave it all they could and the score is indeed full of Beethovenian fingerprints. Yet its continuity is oddly choppy, its mat- erial obstinately unmemorable.

And so to the Mozart, though with a choir some 200-strong and an orchestra of 60, it blasted away at times more like Verdi. Hunt did his best to keep it on the move - indeed the opening of the "Dies Irae" must have set a record for its incredible speed and fury. This remains an iffy score, of course, with its tracts of chorus and solo writing filled out and scored posthumously by Mozart's pupil Süssmayr, and its several sections seemingly added entirely by him. But the undoubtedly authentic passages, so concentrated and direly unnerving in their implications, hit home as ever.