LSO Chamber Ensemble, Barbican, London

Gustav Holst once remarked that among the greatest blessings of his life was having experienced "the impersonality of orchestral playing". But Holst was a trombonist who could expect the odd solo from time to time. For a rank and file string player, having continually to bow and phase a line not as he or she might feel it, but as a conductor imposes on the whole section, must at times feel pretty constricting. Maybe that is why chamber groups drawn from symphony orchestras often seem to play with an extra sense of release and spontaneity, as in this joyous Barbican programme by the LSO Chamber Ensemble.

Gustav Holst once remarked that among the greatest blessings of his life was having experienced "the impersonality of orchestral playing". But Holst was a trombonist who could expect the odd solo from time to time. For a rank and file string player, having continually to bow and phase a line not as he or she might feel it, but as a conductor imposes on the whole section, must at times feel pretty constricting. Maybe that is why chamber groups drawn from symphony orchestras often seem to play with an extra sense of release and spontaneity, as in this joyous Barbican programme by the LSO Chamber Ensemble.

By way of opener, they offered the one-movement string sextet comprising the Prelude from Capriccio (1941), Richard Strauss's last opera and, more startlingly, the first chamber work he had written in 50 years. In the opera itself, the curtain rises two-thirds through the piece, which proves to be the music the stage characters are listening to. In style, it is a nostalgic late-Romantic recension of Mozartian classicism, easefully spun from a few motives passed back and forth, offering the players endless opportunities to meaningfully modify one another's phrasings - well taken in this glowing reading, directed from the first violin of the LSO's current Leader, Gordon Nikolitch.

Four of the strings were then joined by the LSO's peerless Principle Clarinet, Andrew Marriner, for Mozart's own Clarinet Quintet in A, K581, (1789) - composed in Mozart's most financially challenged period, but almost unshadowed in its serenely positive unfolding. The Barbican acoustic tends to beautify but slightly to distance the sound of solo string groups and in the first movement, Marriner sometimes seemed to overbalance. But by the return of the ineffable long melody of the slow second movement, he was completely integrated into the texture; tonguing and floating his long line with an almost uncanny evenness and purity of tone.

Mendelssohn's Octet for strings (1823) is, by general agreement, the greatest work ever composed by a mere 16-year-old. What is less often remarked is how sheerly original it must initially have sounded. The ardent surge of the first movement, intricate sublimity of the second, the scudding filigree of the third and sheer energy of the finale - texture after texture of this work had literally never been heard before.

Indeed, such was the enthusiasm with which the other seven players went at the opening movement, that Nikolitch had to work hard to keep the often stratospherically high lead part audible without coarsening of vibrato, though he also managed to induce a magical stillness in the remote music before the recapitulation. But it was in the scrambling fugal finale that something special really got into the performance: the music seemed almost to lift off in its exuberance. No wonder not a few of a capacity audience were on their feet at the end.