MUSIC / A pill that needs no sugaring: Meredith Oakes on the Premiere Ensemble at the Queen Elizabeth Hall

IT TOOK me by surprise: a non-specialised South Bank audience responding warmly to two Mozart symphonies but reserving its chief enthusiasm for the new piece sandwiched between them. The new piece wasn't pop minimal, either.

Sally Beamish's Tam Lin, a virtuoso scena for oboe with small chamber group including harp and percussion, rode the crest of a single lyric-dramatic surge. Douglas Boyd was an inspired star player at the Queen Elizabeth Hall on Saturday, witty, fiery and exact.

The piece is based on the Scottish tale of Janet, whose love saved the elfin knight Tam Lin from damnation. She held on to him while he changed his form from a snake to a bear to a lion to molten lead, which she threw down a well, whereupon he was transformed into her mortal husband; a set of images that lend themselves to concerto representation of a fairly traditional kind.

The oboe seemed to be Tam Lin himself, opening alone with a compelling series of legato phrases that stretched around an imagined pedal note, now and again twisting back on themselves with a Scotch snap: bagpipe-inspired but abstract and personally discovered, not literally folksy. The incantatory spell powerfully cast here was sustained to the end, where the opening material, after a number of ingenious metamorphoses, made a clear reappearance.

Notable throughout was the freshness of the instrumental colours. Juxtapositions that might seem ordinary enough, such as oboe and harp with cellos added in, or string- type chords curiously tinged with clarinets, were given enough space to really sound, and were made vivid by unusual mimicries and reflections. The intervention of one instrument had an immediate effect on the mood of the other, while imitated phrases subtly adapted their rhythmic character as they changed hands. Dots were joined up, straight phrases started to writhe.

Like Britten, Beamish finds new mileage in familiar effects. A surprise octave-unison passage in hollow contrasting timbres stood out because of the small forces involved; touches of staccato trumpet appeared like drops of blood at the peak of a percussive build-up engineered almost without percussion. Percussion (including bells and vibraphone) was a feature, particularly in the shape-shifting cadenza, but there was little heavy drumming. Ferocious effects were created out of air by piling up entries from a handful of strings, woodwind and brass so that the oboe's sinewy energy predominated.

Tam Lin was commissioned by Mark Wigglesworth's Premiere Ensemble, which seems to have created a new audience for new music while performing the old beautifully. Mozart's Prague Symphony was deliciously suave in quiet phrases, headily explosive in the sequential rallies. All the rhythms were live all the time, with extrovert timpani from Chris Brannick, who in the Beamish was so delicate. Wigglesworth should have trusted himself to let the Andante of Symphony No 40 be slower: the repeated-note triplets were not clear. But generally, heaven.