Recitals of Bach keyboard works on the grand piano get up the delicate noses of the purist musical priesthood. But such performances won't go away as long as pianists of the stature of Daniel Barenboim continue to assert their claims over works like the 48 Preludes and Fugues of the Well-Tempered Clavier, the pieces Hans von Bülow dubbed the pianistic Old Testament (the Beethoven sonatas being the New). And, anyway, there are not many keyboard players of any school who could sell out a large hall like the Barbican with the prospect of nearly three hours of concentrated Bach.

Barenboim's recent recordings of these works have not been well received, especially by the priesthood, and at first in his Barbican account of Book II, one could sympathise with some of the reasons. This was very demonstrative Bach playing indeed, making full use of the piano's sonorities in expansive pieces like such as the D major prelude, even aggressive at times in some of the early fugues, and marred early on by a few too many smudges.

But Barenboim soon settled to his task, adjusted to the acoustics of the hall, scaled back some of the contrasts and gradually drew his audience into an increasingly intimate exploration of Bach's progression through all the major and minor keys. By the time he reached the celebrated F minor prelude at the end of the first half of Book II, he was in full control of his playing and of the audience.

After the interval, he immediately regained this high standard with a masterly account of the great lyric arc of the F sharp minor prelude and the pathos of its accompanying fugue. The final hour was Barenboim at his persuasive best, always obedient to Bach but with something individual and articulate to say, as in the brilliant B Major prelude and fugue which heralds the completion of Bach's extraordinary journey towards the restrained final bars of the 48.