Il Trionfo di Clelia is one of almost 50 operas composed by Gluck, many of which are unknown to the average opera-goer. What makes it interesting, in terms of the history of opera, is that it marks a return to opera seria only months after the first performance of his celebrated Orfeo ed Euridice, widely regarded as the cornerstone of 'reform opera', to which simplicity of plot and music were key.

One of 20 of Gluck's operas set to a libretto by Metastasio, in outline it tells the story of Porsenna, King of the Etruscans, and his conflict with the infant Republic of Rome. As part of a truce agreement, he holds hostage Clelia, a young noblewoman engaged to Orazio, the Ambassador of Rome. Upon hearing that Tarquinio, son of the deposed King of Rome, commander of Porsenna's troops and betrothed to Larissa, Porsenna's daughter, is preparing to launch an attack on Rome to take back the throne, Orazio vows to fight for the independence and freedom of his city and Clelia, honour-bound, swims across the Tiber to join him in his efforts. Impressed by her virtue, Porsenna is persuaded to abandon the fight and give Rome the opportunity of enduring freedom.

A shame that this elaborate story and its accompanying music were made all the more difficult to follow by some pretentious and, frankly, bizarre staging and direction by Nigel Lowery that regrettably missed the plot. Something was amiss right from the very beginning. Half-expecting the curtain to open during the overture and reveal something of the setting beyond the pale, wooden proscenium arch, the audience had to wait until the music stopped for the visual entertainment to begin. Cue Clelia (Hélène Le Corre), true to clichéd form wearing a beige trenchcoat and carrying a suitcase, pacing up and down the stage – but for what? The appreciable tension in the audience was more of the awkward silence type than excitement. Finally, the curtain opened to reveal a minimalist set that appeared to hint at Fascist Italy (yet another cliché), something which was only confirmed by the appearance later on of Clelia and Orazio (Mary-Ellen Nisi) in military uniforms. Larissa (Lito Messini, a late replacement for Burçu Uyar) almost constantly carried a doll, whilst she herself was dressed like one (I couldn't help but think of the artist Grayson Perry...); this is despite her mature astuteness in realising Tarquinio's (Irini Karaiannni) backhandedness.

But what was most irksome was the use of video projection. Granted, there were some clever moments – the projection of a rocky riverbed across the staging to represent the Tiber, and Orazio's commando roll into and under a flap in that staging, for example – but it was largely inappropriately employed. At one point, it was used atop a cardboard box bridge to project tiny, seemingly casually dressed characters, fighting for the freedom of Rome: fine, the audience knew exactly what it represented, but at that point the relevant characters were still on stage and not doing anything. The greatest insult to the largely excellent singing came in the projection of some sort of war speech, scrolling across a banner held by Clelia and Orazio as they performed the only duet of the opera: the audience did not know whether to look at the surtitles and listen to Clelia pledging her trust in Orazio's "great heart" or to try and guess the author of the speech, which could only be done by reading it intently. For me, the result was that I heard bits of singing, read bits of the speech and read some of the surtitles, and had to work out what had happened by reading the synopsis. It was all too much.

Despite this production being overshadowed by Lowery's insensitive and "artsy" direction, the singing was pleasant, and, on occasion, outstanding. Long passages of coloratura were executed with technical brilliance, especially by Nisi and Artemis Bogri, who sang the role of Mannio, Larissa's lover. Le Corre produced some crystal-clear top Cs and Ds, and had an extremely pleasant, if not strong voice. Vassilis Kavayas' voice twice cracking at the top of his range marred an otherwise confidently handled performance as Porsenna. The undoubted star, though, was Irini Karaianni, whose almost contralto voice was big and mesmerising. Her fearsome lower range was put to good use in what was the most dramatic role of the opera. The City of London Sinfonia, under the direction of Giuseppe Sigismondi de Risio, was short of stellar, and could have done with some more careful conducting in the recitatives, but on the whole proved a match for the cast. What a pity that the direction and staging should have marred the performance so seriously.