London Sinfonietta/ Reinbert De Leeuw, Queen Elizabeth Hall, London <!-- none onestar twostar threestar fourstar fivestar -->

A tuba begins to bellow slow permutations of a handful of notes, joined from time to time by a shrieking piccolo and interspersed with crashing tone clusters on the piano. This goes on for some 15 minutes. Then 20 minutes of more regular slow piano clusters backed by eight double basses plus a percussionist hammering on a wooden box; finally, 10 minutes of dense discords for piano, four flutes and four bassoons.

Were this by a contemporary composer, it might be slated for its aggressiveness and poverty of invention. Ah, but it is by the sainted Galina Ustvolskaya (born 1919), Shostakovich's favourite pupil and, as the new South Bank arts supremo Jude Kelly insisted in a long introduction, the epitome of endurance in the face of Soviet oppression.

To which one is tempted to riposte that it is a funny way to protest by perpetuating the conditions against which one is protesting. But back comes the killer blow: Ustvolskaya's music is the expression of her Christian faith. To this one can only assent: enduring her Three Compositions feels like undergoing a stiff penance.

Not all the composers heard in the South Bank's weekend festival, Dancers on a Tightrope: Beyond Shostakovich, programmed by Gerard McBurney, were so exiguous. Valentin Silvestrov (born 1937), present at this opening concert by the London Sinfonietta under the dogged direction of conductor-pianist Reinbert de Leeuw, offered post-Webernian textures that were positively glittering.

Yet it was difficult to find much continuity in the fragmentation of his Symphony No 2. And while his setting of the "Ode to a Nightingale", coolly delivered by the mezzo Susan Bickley, set up a clear image of icy birdsong against slow-moving chords, it offered little response to the changing moods of Keats's poem.

As for the opener, Dancer on a Tightrope by Sophia Gubaidulina (born 1931): this dialogue, in which Andrew Haveron's violin strained upwards to escape the menacing clusters of John Constable's piano, so exactly duplicated its programme description it hardly seemed necessary to hear it at all.