Prom 58: BBC SO/Saraste, Royal Albert Hall, London

As he turned 50 in August 1912, Debussy was at a low ebb, exhausted by the financial struggle to keep his family in comfort and suffering from the cancer that would kill him just six years later. Not least, he was being implacably pursued by the dancer Maud Allan - a kind of Canadian Isadora Duncan - to fulfil the commission of a ballet score entitled Khamma for which she had already paid.

No wonder, in a dark moment, that he is supposed to have muttered to his assistant, Charles Koechlin: "Write Khamma yourself and I'll sign it." In the event he sketched a piano version, but handed most of the orchestration over to Koechlin's expert hand. The 20-minute score was completed in 1913, but Allan never danced it and it has remained Debussy's least known orchestral work; indeed, this reading by the BBC Symphony Orchestra under Jukka-Pekka Saraste was its Proms debut.

It is not so difficult to hear why. The faintly Aida-cum-Salome scenario supplied by Allan centres on a set of sacrificial Egyptian temple dances. These are evoked in menacing, shimmering textures full of harmonic subtleties. In many ways the score proves prophetic of Debussy's next, far more significant ballet, Jeux. What it lacks, what each upbeat so fatally fails to deliver, is memorable thematic material.

Still, Saraste and the BBC SO had evidently prepared it with care - rather more than they had found time to devote to the rest of this East-meets-West programme. George Enescu's Romanian Rhapsody No 1 (1901), once a core light classic with its insouciant drinking tunes and tearaway gypsy fiddling, was dispatched enjoyably enough. But, for all the intermittent beauty of its ideas, Bartok's Viola Concerto (1945), failed quite to take off.

Not that this was Bartok's fault: he died before it was finished, leaving it in sketches for his compatriot Tibor Serly to piece together. The trouble, on this occasion, seemed to emanate from that volatile viola virtuoso Yuri Bashmet, whose elastic concept of rhythm and somewhat sketchy command of figuration seemed, at times, to discompose both conductor and orchestra.

Nor were things quite together for Witold Lutoslawski's Concerto for Orchestra (1954), which Saraste tore into with an untidy haste. But by the crystalline recapitulation of the opening movement, all was immaculately in place; the scherzo-like scuddings of the central capriccio were exquisitely -pointed while the intent passacaglia build-up of the finale held the audience rapt with anticipation. Maybe the scoring is brash at times; maybe the work has one or two grand endings too many. Yet, for all Lutoslawki's later, more Modernist explorations, it packs as much genuine flair and invention as anything he ever wrote.