BBC Symphony Orchestra | Royal Festival Hall, London

There are plenty of "concertos" in which the supposed soloist is the first among equals. Even so, I'd rather the Danish composer Bent Sorensen had dropped the grand generic title for its more evocative pendant, La notte. Which describes perfectly his music's atmosphere of cries and whispers, with the pianist Rolf Hind acting like one of the percussion department for much of the time in Friday's UK premiÿre.

Not that the part written for him is anything but delicate, developing into almost conventional pastel-coloured chords at certain moments, but hardly into a concerto-like dialogue, and never into a vehicle for display.

The early stages were interestingly fastidious - subtle both rhythmically and in sonority - though morse-code repetitions became a touch automatic later on, and at over 20 minutes, the work seemed to reach a standstill well before it ended. Nor was there much point in telling us there were two movements, since the second seemed just like a continuation.

The other novelty in which Michael Schonwandt conducted the BBC Symphony Orchestra was nearly a century old. Alexander Zemlinsky withdrew his programmatic triptych The Mermaid after its first performance in 1905 and left the first movement in Vienna when he fled to the United States. The whole work was put together and performed again only 16 years ago, long after Zemlinsky had died.

Zemlinsky's romantic ripeness was certainly welcome after the chill that Sorensen had created, and Schonwandt conducted with great energy. But you needed an appetite for so much lush effusion, with sumptuous string writing, sparkling solo violin (Stephen Bryant as the mermaid, of course), tinkling highlights on glockenspiel, and glowing brass choruses. The music is well crafted, very much in the vein of Schoenberg's Verklaerte Nacht or Pelleas and Melisande, but smoother and probably less dependent on its storyline than either. Even so, the third movement, which returned to the music of the first, seemed to fall short of its promise.

Stravinsky's concert suite from The Fairy's Kiss - a cubist paraphrase of various pieces by Tchaikovsky - provided a suitably sour antidote to Zemlinsky, but since there was no place for it other than the beginning of the evening, the point was lost. Still, high marks for enterprise.

The concert is broadcast tonight at 7.30pm on BBC Radio 3