MUSIC / All in a world of his own: Anthony Payne on Tennstedt's Mahler Seven at the South Bank

'THE SYMPHONY,' Mahler said to Sibelius, 'must be like the world - all-embracing.' This has always been taken as the key to the remarkable heterogeneity of material and of types of poetry found within a Mahler symphony. But in forging a style whose impurity could embrace a world view, at once comic and tragic, vulgar and refined, innocent and sophisticated, Mahler also, perhaps unconsciously, encompassed another truth that has been less talked about. For each work is also to an extent a record of the creative problems encountered by the composer during the writing of it.

Whereas a composer such as Sibelius refines and excludes material in working towards a perfectly concentrated expression of his central idea, Mahler includes all variant possibilities and even wrong turns. It is as if, with his improvisatory fervour as a composer, he would set ideas on paper at an earlier stage in their gestation than Sibelius. This lends a tumultuous immediacy to his expression and brings ideas into the final product that other composers would not have allowed out of the sketchbook.

One of the most profound examples of the process is provided by the Seventh Symphony, which accounts, perhaps, for its comparative lack of popularity in the Mahler canon. It sounds like a search for an ideal of expression that is not quite sure which way to turn, and in a performance as compulsive and passionately edged as it received from Klaus Tennstedt and the London Philharmonic at the Royal Festival Hall on Friday, the symphony is painfully revealing of the inner workings of Mahler's creative mind.

After journeying from strife to tragic catastrophe in the Sixth, Mahler seems to have been attempting in the Seventh to recapture the optimistic vision of the Fifth, but filtered by the nihilistic experience he had uncovered in the interim. It was a course he was not going to be able to chart successfully until the Tenth Symphony, where serenity is shown as a possible outcome of tragedy rather than the mistaken triumph of the Seventh.

Deep down, Mahler probably realised that he was on the wrong track in this finale, which is why he could only invent unconvincing material. He is known to have had doubts about the work, probably for that reason, and had he lived longer, he might have reconceived the movement, even the symphony, as did Sibelius his own Fifth, which he initially spoilt by being compelled to write it too fast.

Truly, the Seventh is a diary of creative travail and, realising that the cracks are not easily pasted over, Tennstedt shaped each individual movement for all it was worth and drew much brilliant playing. The brass, for instance, attacked with unquenchable enthusiasm in the finale, which Tennstedt understandably made as disruptive as possible lest the triumph seem hollow. Elsewhere there were magic paragraphs, and the mysterious heart of the first movement development was revealed with touching poetry. Perhaps the orchestra was not always on top form, rhythmic ensemble was not always precise at the outset and some wind and brass solos lacked security and refinement, but Mahler's troubling experience was made to live at all stages.