Treading a dramatic path by turns familiar and enigmatic, Hans Werner Henze needed modest forces and little more than an hour of music to fashion his final opera as a hallucinatory epic. Phaedra, as related by Euripides and later by Racine, is a quintessential Greek tragedy: the new bride of Theseus falls in love with his son, Hippolytus; she is rejected by him and cries rape; he is killed; she kills herself. That, in this version by Henze and librettist Christian Lenhert, is the sum of Act 1, barring a few interventions from the goddesses Artemis and Aphrodite and the participation of the Minotaur (who, oddly, remains unslain in this opera).

Act 2 is a post-mortem fantasy that’s as compelling as it is confusing. The ailing Henze, whose allotted span was only five years from completion when he composed it in 2007, drew on a recent brush with mortality to play with notions of life and death, hence Hippolyt (as he is called in the opera) is reborn through the good offices of Artemis and becomes Virbius. Phaedra, now a bird of Hades, flutters round him until an earthquake strikes and Hippolyt-Virbius is crowned the Woodland King.

With so much narrative clutter it’s surprising how cleanly the story is told, thanks to Henze’s musical coherence and riveting orchestrations, all rendered here with admirable virtuosity by the Southbank Sinfonia under Edmund Whitehead. Instrumentation is rich and varied, with plentiful percussion and saxophones of every stripe; yet there is never a cheap moment in a score whose unfamiliar sonorities had me on the edge of my seat. At moments when stage logic threatens to implode, pit logic remains unassailable. Ironically though, given the subject matter, the one essential quality that’s missing from its colours is eroticism.

Director Noa Naamat has created a stylish, kinetically expressive production that feels completely in sympathy with the composer’s world. Henze may have described Phaedra as a concert opera, but the young Israeli brings a literate visual palette and a convincing aesthetic to the table. Each of the five singers is given a strong physical identity so that even when little is happening they all live deep within their characters. No corners have been cut in designs by takis that place the action on a central revolving disc offset by two curving staircases, all set within the magical surrounds of a vast spaghetti-string curtain through which figures materialise and vanish at will. The expert lighting designer, Lee Curran, contributes rigs that descend from above and are integrated into the action, not least at the moment of Hippolyt’s confinement within a cage.

Both Whitehead and Naamat are current members of The Royal Opera’s Jette Parker Young Artists programme, as are four of the singers. (The fifth, an excellent tenor from New Zealand named Filipe Manu, is set to join the scheme in September but was enlisted ahead of time to sing a forthright and powerful Hippolyt.) Let’s cut to the chase and just say that all of them were outstanding. Patrick Terry as Artemis negotiated improbable leaps between his baritone speaking voice and his golden countertenor, while bass-baritone Michael Mofidian was a superb, strutting Minotaur who sang comparatively little yet dominated the action. But it was the pairing of soprano Jacquelyn Stucker as Aphrodite and mezzo-soprano Hongni Wu as Phaedra that set the evening ablaze. These two young singers had the presence and power of true opera stars and, in diva-esque form, they carried all before them.

****1