There's a UK premiere in each concert of the BBC Symphony's Sibelius cycle, but the one included alongside the Sixth and Seventh Symphonies in Jukka-Pekka Saraste's concert was a bit special. New works from György Kurtág are rare events, and a new work in a single movement that lasts more than 20 minutes is rarer still. In fact, … concertante … ("Concertante Op 42"), for violin, viola and orchestra – which Kurtág completed in 2003 but has only now reached Britain, despite winning the prestigious Grawemeyer award for Music in 2006 – is probably the longest single span of music he has produced to date.

Yet, from a composer who has habitually worked on a small, often microscopic scale, often with just a handful of instruments, creating large-scale forms from collections of perfectly fashioned miniatures, the sheer dimensions and sense of musical continuity of … concertante … seems like a wholly new departure.

The work was written for the violinist Hiromi Kikuchi, a regular Kurtág collaborator, and her husband Ken Hakii, principal viola of the Royal Concertgebouw Orchestra, and they are pitted against a vast orchestra that includes 15 woodwind, 11 brass and six percussionists. The full forces are sometimes unleashed in massive climaxes, but more often used as a resource from which Kurtág extracts smaller, constantly changing ensembles to underpin and delicately punctuate the soloists' dialogues.

The arch-like span of the work contains some breathtaking moments: sudden volleys of brass, a fleeting memory of a Hungarian tune, glistening harmonics from the soloists with a tuba grumbling away five octave beneath. Finally, all the music's energy is spent and only whispers remain; Kikuchi and Hakii swap their conventional instruments for skeletal versions that thin the sound still further. It seems both

Available via the BBC iPlayer until Friday.