A few winners of the Cardiff Singer of the World competition have shot to stardom, but most have built their careers more steadily - including the Swedish mezzo Katarina Karneus, who took home the trophy a decade ago. This recital was one of Radio 3's lunchtime series, broadcast live, in which one often finds the more interesting up-and-coming singers in the Wigmore Hall's calendar. In the case of a singer as accomplished as Karneus, currently making an impression as ENO's Xerxes, it is perhaps a surprise that she hasn't already become more of an evening fixture at this venue. At the same time, there was a feeling of restraint, even nervousness, to her performance that made one wonder if, at the moment, she might feel more at home on the operatic stage.

It would be a shame if this is the case because Karneus's supple mezzo is good for Lieder, and her programme showed off its smoothness. Her six Schubert songs, accompanied by the young Swedish pianist Johan Ullen with remarkable dexterity, started a little timorously but culminated solidly in Rastlose Liebe, Karneus plying long, polished lines above the turmoil in the piano part.

The low range and sensuality of Debussy's Chansons de Bilitis suited her even better, as did the sultry middle song of Poulenc's three Métamorphoses, C'est Ainsi Que Tu Es, with the French vowels embedded in her dark timbre. The light-footed virtuosity of Poulenc's Paganini was a good foil. In the Debussy though, there was still the sense that Karneus's warmth and the composer's heat should have combined into something hotter than the slow simmer we got here.

She was at her best in Wagner's Wesendonck Lieder, catching the desperation of Stehe Still! and the languid intensity of Im Treibhaus. Yet it was only in her encore, Strauss's Zueignung, that she revealed how much scope, in size and expression, her voice can have when it is completely unrestrained. If only she had had the confidence to unleash it sooner.