Nabucco is an opera that has baffled and flummoxed directors over the last few years, for no particularly good reason, as it has a strong, comprehensible plot and excellent – if taxing –writing for principals and chorus alike. Recently I have seen it staged with the Babylonians in black rubber robes and ku-klux-klan hoods (Cardiff); with the stage set out like the Holocaust memorial in Berlin (Milan); with both Jerusalem and Babylon represented by clustered bottles of mineral water (Macerata); and now, in Cardiff again, with Jerusalem represented by an all-black set, Babylon in gold, and the chorus largely in street clothes, with the occasional set of fringed garments and skullcap for variety. Rudolf Frey’s most recent excursion with WNO was last autumn’s Maria Stuarda, which featured a lot of Royal Stuart tartan and a pink rubber bustier for Maria. This time round, his set designer kept things minimalistic (though I bet they weren’t cheap), with gold lamé hangings in the Babylon palace scenes and a high table on hydraulics which moved slowly up and down to no particular effect.

Welsh National Opera has an intense relationship with Nabucco. It was one of the first operas they staged, in 1952, in a production by John Moody. Michael Geliot directed it in 1967, and Tim Albery (with the black rubber costumes) in 1995. The WNO chorus sometimes sings the great chorus of Hebrew slaves “Va, pensiero” at the funerals of employees, almost as if it were the company anthem. As a result, one comes to a WNO Nabucco in the hope that the chorus, at least, will be well directed. Not so in this case. The opening scene is, of course, chaotic, as the Temple in Jerusalem has just been torched, and the Hebrews run for shelter through the smoke and ashes. But then an oddity occurs: they start to use hand-signals, like demented traffic wardens doing a training drill. Maybe Frey missed the Monty Python sketches featuring camp square-bashing and Wuthering Heights transmitted in semaphore? We didn’t get the uniforms or the flags, but later on we did get black ostrich feathers attached (by noisy magnets) to balaclava helmets for the Babylonians, clearly a kinky lot of Baal worshippers with questionable taste in vestments. At the end of Act I, when Nabucco fires a pistol into the flies, a huge cloud of glittery confetti flutters down, as if he had shot an over-dressed flyman, and glitter continues to be the theme of the Babylonians and their religion.

The men in the cast were more impressive than the women. David Kempster, after an unsteady start, made a forthright but vulnerable Nabucco, overcoming the initial handicap of a costume that referenced Billy-Connolly-as-Gadaffi, with flowing white locks and a tan general’s uniform. Zaccaria was sung by Kevin Short, who made the most of the deep bass register of the role, and cut an impressive figure in a brown shalwar-kameez. The most promising newcomer was Robyn Lyn Evans as Ismaele, a role which helped to launch Gwyn Hughes Jones at WNO nearly 20 years ago. His tenor voice is clear and well-nuanced, and although the role does not offer huge scope for making an impression, he did a very good best with it.

Abigaille’s entrance was marred by a poor low B at the opening of “Prode guerrier!”, and some wild coloratura on “il fulmine sospeso è già”. The role is a notorious voice-shredder (it was partly responsible for the early vocal decline of Verdi’s wife Giuseppina Strepponi), but Mary Elizabeth Williams clearly has the stamina to tackle it without fearing damage. However, moments of strain were audible in exposed passages, though less noticeable during Abigaille’s various duets and ensembles. I particularly enjoyed her contribution to “S’appressan gl’istanti”, that great false canon towards the end of Act II which joins the principals together in a show-stopping reunion of Nabucco with his daughters and the bold Ismaele. When the chorus came in at the end, I was not the only audience member in tears. Fenena, sung by Justina Gringyte, made a good foil to the heavier voice of Abigaille.

Once Nabucco has made his blasphemous declaration that he is god, the tawdry Babylonian splendour of glitter-curtains falls to the ground, and the king is struck mad. While not actually eating grass like a beast of the field (as prescribed in the Bible), David Kempster did well with his transformation from hubris to humility, and his performance grew more poignant as his voice settled into the challenges of the latter part of the role.

On the podium, Xian Zhang drew an idiomatic reading of the score from the WNO orchestra (already well-schooled in the idiom of early Verdi by Carlo Rizzi), although there were times when her tempi seemed to be too slow for some of the principals. If only the production had not undercut the solemnity and beauty of the opera. Otherwise, I would have been in tears for the second time of the evening once the chorus started “Va, pensiero”. As it was, the most moving moment in the opera came right at the end, when the unaccompanied chorus sang what was the greatest success of the opera’s opening night, the majestic hymn, “Immenso Jehova”.