LSO / Rostropovich, Barbican, London

It is interesting to speculate what sort of Violin Concerto Tchaikovsky might have written had he tackled it six months earlier at the height of his marital catastrophe in 1877.

It is interesting to speculate what sort of Violin Concerto Tchaikovsky might have written had he tackled it six months earlier at the height of his marital catastrophe in 1877. Something wild, dramatic and soulful, perhaps. But such feelings went instead into the first movement of his Fourth Symphony. By the time he embarked on the concerto, in March 1878, he was recuperating in Switzerland, and the result was, for the most part, lyrical and sunny, with any soulfulness confined to the elegant Canzonetta.

Yet maybe an emphasis on elegance and lyricism is only one way of approaching the score, for, within bars of the latest reading by the Russian virtuoso Vadim Repin and the London Symphony Orchestra under the redoubtable Mstislav Rostro-povich, it was evident it was going to be a full-blooded affair. Repin has the gutsiest lower register and tends to thicken his tone in higher lines with a very fast vibrato.

Just as well, here, since Rostropovich was evidently concerned to make the most of every contrast; emphasising orchestral weight in the tuttis - not to say setting a dizzying speed in the finale.

Yet, after this "large-size" interpretation of what remains one of the most technically demanding of violin concertos, Repin insouciantly threw off, by way of encore, Ysaye's insanely difficult one-movement Sonata No 3 for solo violin as though it were child's-play.

Orchestral weight, extremes of contrast, not to say soulfulness under unbearable stress, would seem of the essence of Shostakovich's Symphony No 5 in D minor, Op 47 (1937) - that equivocal document of the darkest days of Stalinism. And of course, Rostropovich was there - not only as a child at the time of the show trials, but later on an intimate friend of the sick, frightened yet inwardly resistant composer himself. Yet, among great-players-turned-conductors, he remains among the least self-indulgent. Virtually every gesture he makes is functional; the beat is clear, cues spot-on, control of rubato and flow natural yet exact.

His performance of the Fifth in the second half of this Barbican concert was notable not so much for its heart-on-sleeve as for its magnificent grading of the opening movement's vast, arch-shape structure, the intense restraint of its slow movement - and all the more shattering for that. The LSO's response, point by point, was total; including some of the most uncannily hushed string playing imaginable.

Did this reading resolve the conundrum of whether the work's obsessive final triumph represented the composer's heartfelt response to "just criticism" or the enforced rejoicings of totalitarianism? No. But then, as Hans Keller used to insist, the difference between verbal, conceptual logic and musical logic is that music can have it both ways at once.