The Tender Land was Aaron Copland's only full-length opera. The premiere - in New York in 1954 - wasn't a success, and little has been heard of it since. The Barbican has unearthed it for the start of Copland's centenary celebrations but, despite the best efforts of all concerned, its flaws are glaringly apparent.

The title is ambiguous: on one level it is the vast American subcontinent, with the potential for exploration and exploitation; on another it represents the adolescent human body, anticipating first sexual experience. The libretto, by Copland's lover Erik Johns, belongs to the 50s style of half-closeted gay writing. Like Terence Rattigan, William Inge and Tennessee Williams, Johns sends his heroine to discover herself after an overwhelming experience with an alluring bit of rough. When the teenage Laurie Moss meets Martin, a hunky drifter, she abandons her restricted Mid-West background to search for personal freedom.

Throughout there are hints of the American dream souring. Women in Laurie's community have been attacked by two strangers. Martin and his friend Top are suspected - but even after the real perpetrators are apprehended, the community still judges Martin and Top guilty because they are different. The McCarthy witch hunts - and perhaps also a suggestion of pre-Stonewall homophobia - hang over the piece.

The problems lie less with the text than with the score. Copland's theatrical imagination was fired primarily by dance, as if the thought of swirling bodies generated the dramatic propulsion that characterises his best music. The tone of The Tender Land, by contrast, is meditative. The score is hampered by an unremitting sameness of pace, and the political overlay isn't given enough clout. The love scenes are unraunchy. Only in the big choral dances in Act II does the score come to life and then we get vintage Copland.

This performance, with Richard Hickox conducting the City of London Sinfonia, was characterised by a dogged, if vain, determination to make the piece succeed. Arresting orchestral textures made up for dramatic paucity on occasion. Laura Claycomb voiced Laurie's yearnings with a shimmery radiance, while Richard Coxon's Martin was dreamy rather than heftily imposing. The performance won't, however, put the score back on the map. The Tender Land has for years been consigned to an operatic limbo - which, is, perhaps, where it really belongs.