Rouse's flute concerto is a perfectly formed arc

Nobody wants to miss target and hit the wall with their launch programme, so everybody's got a blockbuster of one sort or another in their first night. Donald Runnicles and the BBC SSO had Shostakovich's Tenth Symphony. Next Friday in Glasgow the SCO and Robin Ticciati will have Mahler's Fourth Symphony featuring the delectable mezzo voice of Karen Cargill. Tonight in Glasgow Peter Oundjian and the RSNO have the greatest sea epic before Debussy's La Mer: Rimsky-Korsakov's fabulous Scheherazade, complete with its rolling waves of sound in the first movement and its calamitous and electrifyingly orchestrated shipwreck in the finale.

But the RSNO actually has another sensational piece in its first-night programme, and it's one that almost nobody will know, unless they're ahead of the game and already have the RSNO's phenomenal recording. It's a Flute Concerto by American composer Christopher Rouse, and the soloist tonight will be the orchestra's dazzling principal flautist, Katherine Bryan. The orchestra has never played the piece in concert until this week. Moreover, nor has Katherine Bryan. The same forces have recorded it, but not with Peter Oundjian. So this week's concert performances are a Scottish premiere for the concerto.

It is not a new piece. In fact, it's 21 years old. There is a tortuous background to the saga of this concerto but, for now, let me tell you something about the piece because, over the last two months, I have come to know it intimately, through that recording, and have become convinced that not only is it a brilliant concert piece, which you can hear for yourselves tonight, but it is actually a masterpiece.

Let me give you a few navigation points, because you have not heard it here in concert before. Critically, because it was written in 1993 and is a "modern" piece, I should tell you that it is not what you might call "squeaky-gate" music. It is in fact immediately melodic, with quick movements packed with infectious rhythms, here and there a pronounced folk music accent, and everywhere, expressive and breathtakingly acrobatic display opportunities for its soloist.

The key thing to "get" is the shape and structure of the piece: everything then falls into place. Unusually, there are five movements, not the regular three in a concerto. The piece is absolutely symmetrical: the outer movements, one and five, both entitled Amhran (Song) are slow, lyrical movements for the soloist, joined by the string section who play gorgeous, primary-colour chords underneath. Moving inwards from there, the second and fourth movements are lightning-fast pieces, the first of them a March, and the second (ie movement number four) a racing Scherzo with some breathtaking incidents where the flute is joined by lots of sibling flutes, the whole thing goes mental, and the music erupts into a mad Irish Reel. It is enormous, irresistible fun.

That's the quick movements. At the core, the heart of the piece, is the third movement, a haunting, slow and deeply moving Elegy, which is Christopher Rouse's reflection on the horrendous events unfolding in Liverpool as he was writing his concerto: the news of the insane abduction, torture and murder of the toddler James Bulger, which traumatised all of us, including the composer, as we struggled to comprehend the brutality inflicted on that little boy by two 10-year-olds.

In the achingly poignant music of that Elegy, there are two purely orchestral moments, where first the music subsides then, gathering its passion and strength, resumes its statement in a huge crescendo with the entire orchestra piling in at what amounts to an anguished, collective protest at the horror. It is a shattering moment.

So that's the shape. It forms a perfect arc. It is a wonderful, accessible, memorable piece. Katherine and I will have a brief chat about it tonight at 6.45pm in the Royal Concert Hall. She'll bring her flute to give you a flavour.