MUSIC / The dismantling of tradition: Stephen Johnson on Harrison Birtwistle at the South Bank

Subversion isn't what it used to be. These days, composers who write symphonies, concertos or sonatas often do so without irony - or at least without conscious irony. Tradition is again something to be engaged with, fed off. The days of fabulously intricate exercises in self-distancing such as Berio's Sinfonia now seem past - the one period of our musical history which, it seems, no one wants to engage with.

Except Harrison Birtwistle? The views he put forward in a public conversation before Saturday's Festival Hall concert savoured of quiet defiance. His new work for piano and orchestra, Antiphonies, was - he told us - emphatically not a piano concerto. How could it be? Our relationship to romantic tradition is too complicated. Composers who pretend it isn't delude themselves and their audiences. In Antiphonies the soloist / orchestra relationship is challenged and reconstructed.

That's the theory anyway. In fact it was far easier to follow this thinking - or any kind of thinking - in the Birtwistle work premiered the previous evening in Ensemble InterContemporain's Purcell Room concert: Five Distances for Five Instruments. This is as much 'not a wind quintet' as Antiphonies is 'not a piano concerto'. The five instruments were set further apart than usual, their very different colours and carrying-power turned to advantage: to emphasise the layered nature of the musical activity.

In Birtwistolian terms there was nothing strikingly new in Five Distances . . . Familiar devices cropped up throughout its relatively short span: frustrated ostinatos, snatches of high, keening chant, the clockwork machinery winding down at the end. But textures and leading shapes were distinct, the writing pungent and vital and the overall shape graspable. Brilliant, characterful playing by the five members of Ensemble InterContemporain helped, as it did in Elliott Carter's witty Eight Etudes and a Fantasy for woodwind quartet.

But in Antiphonies everything was as clear as a well- churned swamp. No, not quite everything: the gradual emergence of the piano through calmer orchestral lines at the end was a reminder that this was also the composer of The Fields of Sorrow or the magical closing pages of Earth Dances. But it came much too late. The Festival Hall acoustic has sometimes been described, politely, as 'analytical' - as indeed has the conductor, Pierre Boulez. But even with acoustic, conductor, soloist and a visibly determined Philharmonia Orchestra working for it, most of Antiphonies came over in the middle stalls as a swirling, giddying, amorphous mass.

The piece needs to be heard again. Perhaps the Radio 3 broadcast (tonight 7.30pm) will make more sense of it - the presence of a microphone reasonably close to soloist Joanna MacGregor was encouraging. After this hearing though, Antiphonies sounded like a piece so determined to subvert the idea of the concerto that it ended up with no controlling idea at all. For these ears Antiphonies was simply a relentless torrent - a storm of sounds with the compass spinning wildly in the middle. Has the unthinkable happened? Has our most powerfully original composer lost his way?