“To begin with, I didn’t know what to do with the piano,” says Harrison Birtwistle, hardly a promising start for a piano concerto. In the interview printed in the programme, the composer is surprisingly candid about the compositional process. He didn’t like his previous piano concerto very much (Antiphonies, 1992) and set out to write a more interesting piece. He didn’t think hard about the form, and instead went on an “intuitive journey”.

The results are fragmentary and diffuse. Inventive and elaborate music is written for the piano, and for each section of the orchestra, but the connections between these groups and their musical ideas is not often clear. The piano part is mostly made up of sporadic outbursts, brief phrases with terse harmonies but elaborate figurations. Meaningful dialogue is achieved between the soloist and the large percussion section, which often complements the piano’s dark colours with similarly opaque sounds.

Birtwistle’s claim to have composed the work intuitively is borne out by its structure. Most of the musical ideas are short – brief outbursts, melodic figures of just a bar or so – but these fit within larger sections, which in turn add up to a continuous 25-minute span. The work’s subtitle “Sweet disorder and the carefully careless” suggests that the resulting formal ambiguities are deliberate, but there is no hiding the fact that this is a decidedly mixed offering, frequently inspired but just as often rambling and unfocused.

Symphonies of Wind Instruments is, according to the programme, one of Birtwisle’s favourite pieces and “always the model I come back to”. Reason enough then to open the concert with it. In fact, the block structure of the piano concerto owes much to the Symphonies, and hearing it first was a useful handle on the new work. Vladimir Jurowski gave a precise and suitably austere reading, although not so austere that all sense of poetry was lost. The junctions between sections were not as forcibly delineated as they could have been, and the woodwind soloists were invited to shape their phrases. One trumpet split apart, this was a fine performance.

The concerto was written for Pierre-Laurent Aimard, who gave the première in Munich in October and who performed here. He was cast against type. What makes Aimard so special is his ability to bring vitality and colour to modern scores. But Birtwistle was looking for something else – earthy sounds and dark, sullen textures. Any argument that this is not Aimard’s music, though, is countered by his huge recording catalogue, which demonstrates conclusively that everything is Aimard’s music. He gave an excellent performance, by turns questing and questioning, and never breaking out of the anti-virtuosic role the composer had set for him.

But after the interval we got a classic Aimard performance – Messiaen’s Oiseaux exotiques, played as only he can. Real fireworks from the keyboard here, fast, supple and dexterous throughout. The winds of the LPO were on fine form too, well-balanced and never over-restrained. The Birtwistle was fascinating, but this was the highlight of the concert.

It was followed, for some reason, with Stravinsky’s Orpheus, a real comedown after all the theatrics of the previous two works. This gave the orchestra a chance to show off some of its more traditional virtues, elegant woodwind solos, tidy string ensemble (though one pizzicato passage was askew). But the piece sat uneasily with the others, and protestations in the programme that it, too, demonstrates the rotating block technique that Birtwistle has adopted seemed tenuous. A disappointing anticlimax to an otherwise engaging concert.