Prom 34: Ulster Orchestra / Li-Wei/ Fischer

BBC orchestras were resting (or rehearsing) last week, and it was the turn of a visiting orchestra, the Ulster, with its principal conductor Thierry Fischer, to take the stage. The evening began with Mozart - but Mozart shorn of its context. The overture to Idomeneo peters out into the beginning of the opera, so stopping short felt like a mighty pregnant ending.

But it was lightly and perkily played, even in the melancholic moments that shade this work. The ballet music in Idomeneo comes after all the emotional roller-coaster action of the opera has been completed. It's rare to hear the ballet music performed with the opera, although those lucky enough to see the Glyndebourne production this year will have realised how glorious this music is, even if its positioning seems incongruous, albeit entirely conventional for its time.

It's rare, too, for the ballet music to make a concert appearance, but it made a lovely opener, utterly charming, poised and graceful, with some particularly fine playing from the oboes.

The other work in the first half, Prokofiev's Cello Concerto in E minor, Op 58, had never been played at the Proms before. Despite being written nearly 65 years ago, the piece is very rarely performed. Prokofiev had doubts about it - he began it in 1934 but completed it only in 1938. Its premiere in 1938 was met with total incomprehension, and it was not until an encounter with the cellist Mstislav Rostropovich 10 years later that Prokofiev substantially revised the concerto, "simplifying" it technically and giving it the name Symphony-Concerto.

The astonishing young Chinese cellist Li-Wei took on the original version without so much as a hint that this piece is ferocious to play. The concerto is haunted by Prokofiev's great ballet score Romeo and Juliet (written in 1936), both in mood and in shared material. Li-Wei is a fantastic talent, not only fabulously musical, but with a technique that is completely subservient to the music's demands. He is one of very few solo performers (let alone cellists!) who can play really softly in the giant space of the Royal Albert Hall and be heard with utmost clarity. But he also has one of the biggest sounds, easily riding the orchestra. His third movement cadenza was simply riveting.

Kevin Volans is another musician of particular intelligence. His music is expertly crafted but always exceeds the exercise of his craft. Strip-Weave (2002), a revised version of which received its world premiere after the interval, is an ingenious musical parallel to a piece of African cloth, in which the woven strips create a juxtaposition of patterns, some regular, some unpredictable. Through contrasted rhythmic and instrumental blocks, playing against each other, Volans builds up a kaleidoscopic sound world of utmost delicacy.

Finally, a particularly serene performance of Sibelius's Fifth Symphony brought fascinatingly textural parallels with Volans's work.