MUSIC / A rapier wit: Robert Maycock reviews the LSO at the Barbican Hall

WHO said audiences can't tell the difference? The warm applause for the London Symphony Orchestra's principal oboist, Roy Carter, as he entered to play Wednesday's concerto premiere, showed that at least the Barbican's regulars and residents know about brand loyalty. So do its sponsors: the commission funds for Dominic Muldowney's Oboe Concerto came from the Arts Council and Sema Group, a company which has already given the LSO an endowment for the principal's position.

From Muldowney they got a piece that typically preferred the rapier to the blunderbuss. It teases and intrigues from the start - a decoy solo planted in the orchestra to be picked off by the real one. The composer called the concerto a 'song cycle for oboe and orchestra', and the oboe does chiefly show off long graceful lines. Against that the orchestra, light in numbers and delicate in attack, enjoys itself by playing games with rhythm and colour and in harmonies that keep hinting at the familiar, a touch of Gershwin here and Ravel there, before dancing on to something new.

You may, after a while, catch yourself wishing they would swap roles more often. Eventually the oboe turns active, setting off in a clear-cut finale theme that crosses the bounce of Poulenc with the suaveness of Ibert. But the music does not behave for long like a normal finale: the orchestra briefly opens up a chasm, groaning beneath the solo's exquisite agony, then the tricks of shifting and simultaneous speeds are subdued and the work ends quietly with its high spirits gone. Where is the real Muldowney in all these hints and half-lights? Maybe lurking just under the surface, the controlling mind that sets up the games. Repeated listening might flush him out; a record for NMC was due to be made the next morning.

Michael Tilson Thomas and the orchestra, who matched Carter's fine lyrical playing with their own poise and precision, went on to a contrasted, head-on encounter with Mahler's Symphony No 5. Things did not sound as they looked, as Tilson Thomas took a running lunge at the second violins, pirouetted on the rostrum and stopped just short of inviting the rear stalls to join him in a waltz. Nor was the opening typical in its over-pointed fanfares and slowings into themes. The exaggerations proved to have a purpose: this was a severe, intense and sustained exposure of the symphony's skeleton, its multiple layers carefully disentangled and presented beneath an unblinking eye.

With years of habitual, accumulated Viennese charm stripped off, the music once again became Expressionist rather than Romantic. Only in the Adagietto did this refusal to wallow become mannered; the strings' spectacularly timed withdrawal of tone at the end of the movement was more thrilling than moving. Still, we were consistently at the opposite end of the spectrum in Mahler performance from the Freudian school, which makes his music sound like the analysis and cure of a particularly neurotic patient: no wimp, this case.