Prom 26: BBC National Orchestra of Wales/Fischer, Royal Albert Hall

Heinz Holliger is both the greatest oboist in the world, and Switzerland’s most significant contemporary composer. And he's celebrating his seventieth birthday in style, having just recorded a piece entitled "HBHH" - "Happy Birthday Heinz Holliger" - by the centenarian Elliott Carter. Meanwhile ECM has just released his extraordinary "Romancendres".

You don’t have to be Sherlock Holmes to work out the symbolism in that title, which is made up of the French words for "novel" and "ashes", but you need a taste for code-cracking to appreciate the convoluted creativity which went into that work's making. The tortured relationship between Robert and Clara Schumann has never been so subtly reflected, as in this ghostly rumination on a work which Schumann's anguished widow burnt, leaving just a few clues to how it would have sounded. "I wanted to listen to the sound of those ashes," Holliger said recently, "to see what they could create."

This metaphor might also stand for "(S)irato", the Holliger piece which got its belated UK premiere in Prom 26. And its title plays a similar game, being a superimposition of words from two languages: the Italian "irato", meaning "enraged", and "Sirato", being the Hungarian for a funeral lament. Holliger's lament is for his composition teacher, the Hungarian composer Sandor Veress, whose quest for citizenship outside the Communist world he tirelessly championed. And though the work is subtitled "Monody for large orchestra" - suggesting a single musical line - it's some time before we realise that that is indeed what it is.

It starts with a series of muffled outbursts, some of them bright and high, others low and rumbling, in an unrelenting atmosphere which was effectively set up by the BBC National Orchestra of Wales, under Thierry Fischer's incisive baton. Gradually one realises that its seeming randomness is meticulously controlled, and that the buzz, grumble, and shriek is a dour form of "embellishment". A cimbalom is heard, and the string players briefly strum their instruments "quasi guittara": as the sound-world becomes Hungarian, the sonic mists clear, and a shining beauty emerges, leaving in its wake a wonderful stillness. It seemed a pity to dissipate this stillness with Prokofiev’s exuberant "Romeo and Juliet", well-played though that was.

The first half of the evening was devoted to Mendelssohn, with a glittering performance of his first symphony, and with Isabelle Faust as the excellent soloist in an exquisitely refined account of his Violin Concerto.