Bruckner fans are a dedicated and erudite bunch: a quick stare at the Wikipedia entry or the Bruckner Society's website gives you more to read than you can possibly imagine about Bruckner's life and approach to his work, and last night's performance of his unfinished Ninth Symphony had more audience members poring over copies of the score than most concerts.

There's certainly plenty to pore over. Bruckner occupies a unique position in musical history: his symphonies are firmly grounded in the German romantic tradition, but they are full of musical techniques that would come into their own in the twentieth century. In Bruckner's ninth symphony, you can hear pointers to the styles of many composers that followed him. So the music is polyphonic, with the orchestra often split into several voices that are distinct and not always obviously related - but to a much less radical degree than Mahler. The voices are often in apparently unrelated rhythms - but the whole is not outrageously polyrhythmic in the way that Stravinsky sounds. Percussion plays a huge part in the symphony's backbone - but it's just a single timpani player. And the harmonies and chord progressions are clearly out of the romantic norm - but not as much so as Shostakovich or Schoenberg.

I was taken by one stylistic trick of Bruckner's own: the way he uses recurring themes. A theme is stated powerfully, and then developed; after a few key changes, the music seems to have come to a dead end and stops. But what Bruckner has done is to set your ear up for a restatement: after a pause for breath, the original theme is reintroduced with greater force than before. There are several of these motifs in the ninth symphony: it makes for a work that is extraordinarily satisfying to listen to, and you get a sense of being transported by powerful waves of feeling.

There is so much going on in this symphony that it takes extraordinary precision to get the best out of the music: it would be so easy for the whole thing to turn to mush. Conductor Günther Herbig may not be a household name in England (he has had a long and distinguished career in Germany and the United States), but he clearly knows his Bruckner and knows how to drill an orchestra: the London Philharmonic showed from the outset that they were tightly knit together. The complex interplay between voices was wonderfully lucid, and when the orchestra came together for the big power chords, the Royal Festival Hall was fairly shaking. In particular, the first and second movements have some fabulous brass writing (it's a huge 16 instrument brass section) and the LPO's brass players were right at the top of their game.

The second movement, a powerful scherzo and manically fast trio, was even more potent than the first. I was less taken by the third, in which I found my attention wandering for much of the movement until everything clicked again for the concluding passage. After an hour of symphony, however, I was ready and prepared for the fourth movement - which, of course, doesn't exist, as Bruckner died before he could complete it. There have been several attempts at completion by other composers, but none of them are widely considered as totally satisfactory, and the LPO followed the practice of most current orchestras in choosing not to play any of them.

The Bruckner was preceded by a Mozart Piano Concerto, the C major K503. It was an odd piece of programming, since the two works are polar opposites in style: the Bruckner is intense and immersive, the Mozart gracious and elegant. I'm afraid I had the clear impression that the Mozart wasn't Herbig's thing: it was conducted cleanly, accurately and pleasantly, but with little to fire the imagination. Pianist Andreas Haefliger played with impressive technique and evenness, but it was all a bit dry and I found it forgettable. Partly, this is because there's something I don't like about the sound of that particular piano in that particular hall. I don't understand the cause, but I find the piano sound to be bright and clear but lacking in richness and depth.

Bruckner's symphonies get relatively little attention, particularly compared to the huge amount that is being lavished on Mahler in his two anniversary years. On the evidence of this performance, the first two movements at least, Bruckner merits a much closer look: his music is powerful, complex and contains a great deal to expand the mind. And for an audience brought up on romantic orchestral work, it's considerably more accessible than much of the twentieth century repertoire.