THE strongest impression of Sally Beamish's new flute concerto Callisto, premiered last night by the RSNO, with soloist Sharon Bezaly and conductor Martyn Brabbins, is this: I know of no other composer who constantly regenerates herself in music as does Beamish.

Think of the throaty, primal roar of her saxophone concerto, the warravaged pages of her violin concerto (which the RSNO will play tonight in Edinburgh) , and the heartfelt lyricism of her second viola concerto. There is no recycling from work to work, no falling back on the tried and trusted, no cliches.

In each piece Beamish finds new ideas, new techniques, and unfailingly fresh music.

So it is in Callisto, a programmatic piece with a good tale of gods, goddesses, jealousy, and transformation, as Martyn Brabbins pointed out in his helpful introduction. But is also an adventure in abstract music, an exquisite instrumental narrative of atmospheres, moods, and changing characters, all stunningly evoked by Sharon Bezaly on the full range of flutes: regular, alto, bass and piccolo.

Contemplative, melancholic, whimsical, dartingly mercurial, and, ultimately, piercingly penetrative, the music Beamish has conjured for the platoon of wind instruments was rolled off with dexterity and ease by Bezaly. But perhaps even more impressive was the clarity of the music, played with high rhythmic definition by the RSNO, and helped immeasurably by the ravishingly sensitive orchestration Beamish has lavished on the composition.

It's a beguiling, beautiful piece, written by a composer at the peak of her prowess, directed by a conductor at the top of his game, and played by a flautist like no other. It will be recorded, but we should hear it again in concert.

The rest of the programme, Mahler's lovely Blumine and Sibelius's First Symphony, will be covered in the review of Beamish's violin concerto on Monday.