The overture to Guillaume Tell, a four-part symphonic poem far more subtle than its Lone Ranger finale suggests, opens with a ‘Dawn’ sequence played by five solo cellos. One of these, the WNO cello-section leader Rosie Biss, played her part from a platform on the stage, under a wrecked cello (I hope one of less value than the one she was playing), before being carried off into the wings by the vicious Austrian occupying army. The broken cello stayed aloft, as a vivid image of discord.

When the overture ended, the Switzerland that appeared was a bleak vision of broken ice fields, far from the chocolate-box lakeside scene of convention. Caspar David Friedrich’s painting The Polar Sea, skilfully reproduced by scraping wire brushes against Perspex panels to produce a landscape in fifty shades of grey, provided the backdrop of an icy, monochrome Switzerland under Austrian domination. Here the downtrodden people, dressed in subfusc shades of beige, faun and taupe, kept a few colourful scraps of wedding finery hidden in boxes, to be whisked out for celebrations and stashed again before the authorities spotted them.

The period of the production could be dated to around that of the opera’s first performance in 1829, if one ignored the steampunk armour of the Austrians. This pointed up the fact that during Rossini’s lifetime and beyond, his last opera was frequently banned, more frequently cut, and rarely given full-length performances. David Kempster, one of the best of Wales’s current splendid crop of bass baritones, made a fine, heroic figure as William Tell, and with Leah-Marian Jones eloquent as his faithful wife Hedwige, and Fflur Wyn as his brave son Jemmy, the family symbolised a happy, free Switzerland that might emerge the moment the Austrians got off their land.

The audience got somewhat confused when Richard Wiegold, who has one of the most immediately recognisable bass voices around today, left the stage in his role as Melchthal, the village patriarch, only to reappear, minus tricorn hat, red waistcoat and glasses, as Walter Furst, a Swiss partisan who brings the news of Melchthal’s death. This piece of frugal casting was, however, the only sign of penny-pinching in a vocally well-cast production. An example of money well spent was the excellent corps de ballet, choreographed by Amir Hosseinpour. Their hilarious wedding-dance, with a good deal of saucy puppetry behind an embroidered bedspread, livened up the drab stage no end.

Sadly, Gisela Stille, who was to have sung Mathilde, the Austrian noblewoman who loves Melchthal’s son Arnold, was not well enough to sing the role, but was able to walk it through, while Camilla Roberts essayed the almost impossible task of singing it from the wings. Roberts was at her best when she sang Mathilde’s great aria, “Sombre forêt”, but her duet with Arnold was hard to coordinate with her lover standing 40 feet away from where she was singing.

The hardest role to cast in William Tell is that of Arnold, a high tenor part originally created by Rossini’s pupil and friend Adolphe Nourrit. Nourrit was the first French tenor to bring an Italianate timbre to the head register of the voice, and he could reach a top E (though he only did it in private). There are plenty of top Cs (to be sung full-voice, not in the earlier French style of falsetto) and Barry Banks took them like so many hurdles at a point-to-point, sailing over them with grace and style. He was physically hampered by a wig that appeared as if it were about to sprout four legs and scuttle away into the wings, and by breeches that made him look as if he had been sawn off at the knees, but he did not let these get in the way of a fine performance which made Arnold the worthy co-hero he should be.

My favourite performance of the evening, however, was that of Clive Bayley as the evil Gesler, who received a good, old-fashioned pantomime booing when he took his curtain call. Confined to a wheelchair while wearing full armour (including, in early scenes, a stag’s head helmet complete with foot-long antlers), he did not let these clanking, squeaking accoutrements get in his way, as he organised the cruel tournament in which Tell has to shoot the apple off his son’s head.

As is so often the case with Welsh National Opera, the finest music making came from the chorus and orchestra, under the baton of Carlo Rizzi, one of the best Rossini conductors alive today. The individual voices of lower woodwind and strings, and the haunting horn-call of the ranz-des-vaches, all gave voice to the poignancy of the Swiss people yearning and striving for freedom. The final chorus, “Liberté, redescends des cieux”, spine-tingling in its beauty, with the great theme rising from a simple ostinato figure, is as great as any finale before it – and after it, perhaps, right up to the conclusion of Wagner’s Ring