Premiered in Vienna in 1770, Paride ed Elena is the least well known of Gluck's mature operas. Hearing this concert performance with Paul McCreesh conducting the Gabrieli Consort and Players, you understand why. Its subject - the elopement of Paris and Helen from Sparta that precipitated the Trojan war - is primarily erotic, and Gluck, at that point in his career, had not found a musical language capable of portraying sexual passion.

Dramatically, it is essentially a three-hander: the protagonists are the two lovers and Erasto - ostensibly Helen's minister, though, in reality, the disguised Cupid, who aims to ensure that Helen gives in to Paris's desires. This takes some doing, for Gluck's Helen, far from being the sensualist of popular imaginings, is very much a Spartan: tough, resilient and moralistic.

The score charts Helen's crumbling resistance in the face of Paris's growing impatience, as her austere music gradually gives way to his importunate lyricism. Some of the arias are beautiful, but too much of it is cast as extended recitative, which goes on forever and wears thin after a while.

McCreesh fails to disguise the resulting longueurs, though his commitment is never in doubt, and he is very strong when it comes to the contrast between Trojan sensuousness and the militaristic Spartan music, which also contains intimations of the conflagration to come. Written for a castrato, the role of Paris lies too high for a modern-day countertenor. McCreesh has opted to work with the Czech mezzo Magdalena Kozena, who looks like an art deco androgyne and makes a fabulous sound, velvety in her lower registers and displaying high notes of bell-like clarity. Susan Gritton is the waspish, arrogant Helen and Carolyn Sampson a silver-toned, cheeky Erasto. It is finely done, though the work itself remains unconvincing.