MUSIC / In the balance: Nicholas Williams on the London Philharmonic at the Festival Hall

How do you balance a second half consisting of Mahler's Tenth? The London Philharmonic does it by simple mechanics. Before the interval of Sunday's Festival Hall concert, the arching, formal spans of Mozart's Sinfonia concertante acted as a lever attached to the dense counterweight of Birtwistle's Ritual Fragment.

It fulfilled its opening role perfectly, drawing a hesitant audience into a semi-circle of players, each taking a cue - without conductor - from the others in a threnody for the impresario Michael Vyner. The draw was in the theatrical action, as performers in turn moved centre-stage to offer their wreath of melody. There were elegant riffs from violin, horn and bassoon, with a stirring part for bass drum.

Theatricality also characterised the Mozart: Thomas Zehetmair (violin) and Tabea Zimmermann (viola) were as lithe as any operatic duet. The conductor, Mark Wigglesworth, grasped the work's pulse without hesitation. The soloists maintained the pace through the Mannheim crescendos, with playing that was rarely passionate, yet as perfect and expressive as a statue. Oboes and horns, jovial in the second subject, turned plaintive in the elegaic Andante. Here Zehetmair made up for a coolness of tone with playing of tender nuance, while Zimmermann ravished the ear with sonorous counterpoints.

Any presentation of Mahler's Tenth in Deryck Cooke's performing version is an event. This one, however, initially failed to take fire, despite Wigglesworth's bold decision to conduct from memory. Too often his tense, personal reading ran the gauntlet of indecisive playing. There was little will in the various appearances of the soaring Adagio theme to match accuracy with Angst, and at crucial points in the first movement imperfections of ensemble took the polish from otherwise committed playing.

Not everything was hit and miss. There was plenty of spirit and smart phrasing in the Purgatorio, and the Landler sections of the second movement were done in style. The finale drew the greatest unanimity between conductor and orchestra. Solo flute was an ethereal voice in the gloom, strings compact yet generous. Intention and action were in harness, even if the best moments, as always, were those written into the score.