Ravel's Piano Concerto in G, written between 1929 and 1931, is often seen as the musical embodiment of art deco elegance - a work of exquisite beauty and great charm that can all too easily tip towards frivolity. French pianist Claire-Marie le Guay's performance with Louis Langrée and the London Philharmonic was a darkly nostalgic affair that uncovered great emotional depths beneath the piece's glittering surface.

Le Guay appears to be a formidable pianist. Her tone was weighty, conferring moments of jaggedness upon the jazzy sparkle of the outer movements and hinting at undercurrents of tremendous passion beneath the flow of the central adagio. Sculpting each phrase with great finesse, she was never vacuously showy or flippant. Langrée conducted with edgy brilliance, and the LPO responded with playing of sleazy virtuosity.

This was a great achievement, as was the performance of Ravel's Mother Goose Suite that preceded it. An immaculate judge of mood and colour when it comes to French music, Langrée opened up a beautiful if occasionally uneasy soundscape in which innocence teetered on the brink of experience and shafts of loneliness and sensuality could be heard in the silky strings and acerbic woodwind.

Yet Langrée can also be variable. Beethoven's Seventh Symphony came after the interval, and the conductor's performance, though by no means negligible, was altogether less impressive. Despite his enthusiasm, some of it seemed overconsidered, as if he were unwilling to let the music expand towards the requisite extremes of Dionysiac elation. There were moments of rhythmic uncertainty, leading to a drop in tension. And the LPO's playing, so perfect in the Ravel, was altogether less assured here, hampered by occasional moments of imprecise ensemble.