Spreading a little happiness

David Sawer - whose the greatest happiness principle had its London premiere at Thursday's Prom - is no longer the wild and wacky composer (cum performer/director) of avant-garde music-theatre pieces he once was, but a sober deliverer of orchestral and other scores demonstrating more conventional virtues. One of the liveliest British composers of his generation, he's unlikely, however, to abandon the search for an external stimulus, usually a visual one, for each work he writes.

The title of the greatest happiness principle refers to the 18th-century philosopher Jeremy Bentham's ideal of the greatest happiness for the greatest number. The circular design of the Millbank Penitentiary - which stood where the Tate now is, and was evidently conceived on Benthamite lines - provided the composer with his starting point. These triggers to Sawer's creative processes can be reflected in surprisingly direct ways. This 13-minute work is, for instance, built on a circle of fifths; a concerto- for-orchestra-like focus on individual players and instrumental sections suggests the method of observation apparently used on the Millbank prisoners themselves.

While it isn't as ambitious in conception as his 1992 Proms commission, Byrnan Wood, Sawer's new piece quickly transcends its John-Adams-ish opening. Unexpected shifts of speed and focus sometimes arrest the momentum. Spotlighting of instruments is made a virtue, even when seemingly random: delicate runs soon disrupt any threatened minimalist tendencies of the more crowd-pleasing variety; the first big climax is quickly interrupted by a little figure for cor anglais and bassoon, soon taken up elsewhere. Scale patterns and triads constantly lurk in the background.

Sawer shows himself capable of developing his material with due care and attention to its cumulative potential as well as its moment-to-moment fascinations, with a firmly built, if brief, climax two-thirds of the way through to match the earlier one. The end, however, is a surprise: suddenly unconducted, the music threatens to disintegrate altogether before the final bars attempt a sort of coherence. Sawer dismisses any symbolic interpretation of this, but the inspiration is pretty clear.

In the Bartok Piano Concerto No 3 that followed, while Stephen Hough was an assertive and volatile - if also, when appropriate, a subtle and responsive - soloist, the BBC NOW's new conductor Mark Wigglesworth couldn't, for instance, persuade his strings and woodwind to produce either the precision or the atmosphere necessary to match the pianist in the second- movement alternations of solo and orchestra.

Sibelius's Second Symphony was a brave choice. Wigglesworth reduced the pauses between movements to a minimum, but internal tension was only the more fitfully realised. The performance, if full of closely observed detail, never really caught fire.