Classical; London Philharmonic Youth Orcehstra; Queen Elizabeth Hall, London

Something of a post-war success story, the British youth-orchestra tradition survives despite straightened circumstances, doing what comes naturally: playing new music with a flair and dedication that can put full-time groups in the shade. Founded in 1922, the London Philharmonic Youth Orchestra draws on students from the country's music colleges and takes up Birtwistle, the parent ensemble's resident composer, with a dedication recalling the Leicestershire School Symphony Orchestra's work with Tippett in the 1960s. Youth and innovation should belong together. With this venture, players on the verge of professional life have the chance to tackle repertoire which will accompany them throughout their careers.

In their first concert of the year, at the QEH on Sunday, they rang the changes on the three Bs - Britten, Birtwistle and Beethoven - to make intriguing, if unlikely, partners in an evening of gripping musicianship conducted by Andrea Quinn. By way of prelude, the impressionism of Britten's Four Sea Interludes from Peter Grimes put the orchestral talent in perspective. The unadorned lines of "Dawn" showed up some hesitant articulation in the violins; a rogue player was apt to intrude an aura of brushed open string resonance in quiet passages. But the discipline of "Sunday Morning", "Moonlight" and the violent, Mahlerian "Storm" was impressive, with Quinn's fierce, extrovert direction, overbearing at first, clearly emerging as a force that was willing the players in the direction she wanted.

Come Gawain's Journey, Birtwistle's extraction of music from his second full-length opera, the band had found their stride. Trumpet and euphonium replaced operatic voices, imparting a haunting cavernous timbre to the whole. The broad gestures were incisively delivered: the plangent fanfare that marked Gawain's decapitation of the Green Knight, and the shuddering bass drum signalling the last throes of the orchestral frenzy that is the third and final vision of the hunt. With the exception of an oboe lullaby, the piece was obstinately loud. Even so, more judicious balancing of strings, wind and brass would have enhanced the illusion of dramatic power and space. So often in contemporary scores, the regions that separate the main thematic signposts become receptacles for bland atonal padding. Not so in this work. Significant details followed a life of their own: for example, the pattern of fan-like chords spreading outwards through the texture at various points, which unveiled intriguing new sounds at each reappearance.

Though rarely associated with Birtwistle's musical ethos, Beethoven was himself a composer obsessed by exploring a "certain idea" of dynamic movement, uniquely his own and uniquely expressed in his Seventh Symphony. Though some shaky woodwind entries and horns, clearly tired by their previous exertions, took the shine off Sunday's performance, this was a spirited account of a broad-limbed work whose boundless energy requires a firm hand. Orchestral flaws seemed most poignant in the exposed pages of the slow movement. Elsewhere, it was Quinn's unyielding rhythmic drive that proved the dominant force, whether in the dancing first movement or the finale's motoric conclusion.