sound:

Now, before she reaches for the phone to call her lawyer; before Robert von Bahr, founder of the BIS record label and a resolutely fierce champion of Beamish, puts out a contract on me; and before her fellow composers who love her dearly organise a lynch mob, I'd better explain what I mean.

Actually, I pretty much mean exactly what I say. Beamish is already renowned for her versatility. Her repertoire of compositions includes two symphonies, a community musical, an opera and a portfolio of 15 concertos for solo instruments ranging from the orthodox classical instruments to the accordion (for James Crabb) the panoply of percussion (for Evelyn Glennie) and the saxophone (for John Harle).

She has worked with jazz musicians including saxophonists Tommy Smith and Branford Marsalis; she has a developing relationship with traditional music which will result, in the future, in a double concerto for fiddle and clarsach that she will write for Chris Stout and Catriona McKay with the Scottish Ensemble.

She is involved in developing a theatre piece with actor Sam West around a Middle English text featuring the Seven Deadly Sins. She is writing a new percussion concerto for superstar Colin Currie which will have an unusual, balletic slant.

Her very contemporary classical music has been played on early music instruments by the Orchestra of the Age of Enlightenment. She has recently been commissioned by the Rascher Saxophone Quartet to compose the "missing" middle movement in Bach's Third Brandenburg Concerto. She has been nominated for a British Academy of Composers Award for an extraordinary piece entitled Divan, written for the early music group Fretwork, using the texts of a 14th-century Persian poet, classical Iranian musical techniques, birdsong, and scored for counter-tenor, oboe, a consort of six viols and optional percussion.

See what I mean? In the breathtaking range of styles in which she operates comfortably, Beamish is everywhere, ubiquitous, all over the place.

And as if to underline that versatility, on two different record labels there are three new CDs of her music which are receiving almost simultaneous release. One, on the BIS label, is long-awaited and features her First Symphony, her Violin Concerto and her Flute Concerto with the RSNO and Martyn Brabbins. Another, on the Delphian label, includes her Seafarer Trio, which is played by the Fidelio Trio and incorporates the eponymous Anglo-Saxon poem, read by Alexander McCall Smith.

And the third new disc featuring her music is a concept album on the BIS label with cellist Steven Isserlis, who asked Beamish to make an arrangement and a re-invention of a Debussy Suite for Cello and Orchestra.

There is a long story behind this one, but the resultant, exquisitely-orchestrated suite is already making its way into the repertoire and contains at least two absolutely beautiful short numbers that will find their way into permanent occupation in the Smooth Classics type of radio programming.

This remarkable breadth of stylistic expertise, especially at the moment with the strong influence of jazz, is having a huge impact across her compositional work, even filtering into her classical compositions.Tomorrow night the BBC SSO and associate guest conductor Andrew Manze will give the world premiere of Beamish's latest composition, Kirschen (Cherries).

Over the next two seasons, the SSO will perform all four of Brahms's symphonies. They have commissioned four contemporary composers each to produce a short new piece to sit alongside the Brahms symphonies; it might be a homage, a response, a reflection, whatever. Sally Beamish was asked to write a companion piece to Brahms Four, and it had her scratching her head.

"I made several false starts; it was really difficult. It's not like doing something based on a baroque style, which I've done a lot. With this big piece of classical/romantic music, it was really hard to get in there: you're so controlled. I didn't feel there was any way in."

Then she remembered her string quartet, Opus California, where she did a jazz take on a Beethoven quartet, and wondered what would happen if she did a similar thing with a Brahms symphony.

"I took the four movements of the symphony and made four tiny movements, each of which is about the length of a song and each relating to the movements of the symphony in a different way. Each is very jazz-inspired, more than any other piece of mine. It's almost like a big band piece. The third movement is a complete romp: I've taken the plunging opening of Brahms's third movement and made it big-band-y. The whole thing is a big scherzo; a real joke."

For her finale, she went back to the bass line of the Bach piece that inspired the finale of the Brahms symphony. "As soon as you play some of these baroque bass lines on a string bass it becomes jazz; and that's what I've done, really. They're all short, the four movements," she smiled. "There's no time to get bored; if you don't like one you might like the next."

And the title? "Brahms said more than once that he wasn't happy with the Fourth Symphony. He said it sounded like kirschen: unripe cherries; a bit sour, not quite properly finished."

And neither is the evolution of the jazz demon inside the brain of this brilliant woman properly finished. To cut a very long story short, when jazz saxophonist Branford Marsalis played Beamish's saxophone concerto at the North Sea Jazz Festival he was smitten by the music. He told Beamish that he was going to cut an album with his own quartet, but he wanted strings on it, and he wanted Beamish to write the music.

"He specifically didn't want string backing. He wanted something that was interesting, something that they could bounce off. And it's turned into a project that we've been working on for a couple of years now."

She signed up for Richard Ingham's jazz course for professional musicians at St Andrews University, where she's now in her second year. And, having been signed up by a Norwegian music publishing house, she's taken herself off to another university course and is learning Norwegian. In fact, she feels an increasing tendency to look northwards. Her Seafarer Trio receives two performances at the Sound Festival this week with her brother, actor Oliver Beamish, narrating. Her record company is Swedish. The orchestra on her new Steven Isserlis disc is Finnish. Her forthcoming concerto for Colin Currie is a three-way commission from the Swedish and Scottish Chamber Orchestras and the Bergen Philharmonic. Her links with the St Magnus Festival, where she works with Alasdair Nicolson on the St Magnus Composers' Course, are very strong.

From jazz to traditional music; from contemporary to early music; it's all there. Sally Beamish does the lot. Versatile? I should say so.