Colm Carey | St John'S, Smith Square, London

It has taken many years for people to recognise Bach's The Art of Fugue as music, rather than a collection of intellectual crossword puzzles for the eyes - and possibly the ears - of scholars. Bach did not specify instruments but laid out the music on separate lines to make the counterpoint clear; most of it lies within the reach of 10 fingers. All sorts of arrangements have been tried, more or less colourful, to sugar the pill of Bach's learned counterpoint. In Vikram Seth's novel An Equal Music a string quartet agonises over the problems of performing it with instruments whose normal ranges do not quite encompass all the notes. In fact string quartets have performed it successfully, but, increasingly, keyboard-players have taken over.

On Thursday the organist Colm Carey performed 12 of the fugues, leaving out the "mirror" fugues (not easily managed by a single player) and canons, but including the fugue that Bach left incomplete, breaking off just after the point where he introduced the musical cipher of his surname. It was the only fugue in which Carey introduced the pedals. In each of its sections he also increased his selection of stops, though discreetly, building tension, then stopping where Bach did, leaving us, very effectively, in an agony of suspense.

In each of the 11 fugues before that, Carey confined himself to one of the St John's instrument's three manuals, choosing a new registration, or set of stops, for each fugue, with only one addition, of a mordant reed, half-way through the long 11th fugue. He usually opted for sober colourings, lightening the fourth and ninth fugues by playing them at four-foot pitch, and putting on the pomp of the Great Organ's principal chorus plus reeds for the swaggering sixth fugue, in which Bach consciously aped the "French style".

As for the notes themselves, he enunciated them clearly, not quite staccato, and eased the tempo just a bit where it seemed natural, to mark the end of a section or a point of arrival. Only the 10th fugue, which he took more slowly and did not decorate, began to feel a bit ponderous. For the rest, it was 65 minutes of gripping listening, much enhanced by Jeremy Summerly's good-humoured and clear introduction.