In a programme article, David Cairns describes The Marriage of Figaro as “a wonderfully funny opera”, but you would never know it after attending Olivia Fuchs’s laboured, strait-laced and humourless new production for English National Opera. Things begin to go wrong during the overture, as a team of gardeners crosses the stage watering the rose garden that is the visual idée fixe of Fuchs’s theatrical concept. Then a gaggle of kitchen maids comes on to pluck stuffed geese, throwing feathers around — another idée fixe, but search me as to why — in time to the music. We’re in a sort of Gosford Park-meets-Upstairs Downstairs milieu, circa 1930, so Mozart’s evocation of a hothouse Andalusian atmosphere, full of erotic promise, goes for nothing here.

The lady of the house is no Kristin Scott Thomas, on the lookout for a hunky bit of rough trade, but a mopey, Queen Mary-like matron, bewailing her failed marriage and mourning a lost child. When the action proper starts, Figaro measures up the disused baby room for his marriage bed, while later, in her great moment of truth in Act III, Countess Almaviva clutches a small garment.

So, the Almavivas’ childlessness is the motive for the Count’s philandering. It’s nowhere in the libretto, needless to say, and it casts a mawkish pall over this Figaro. Generations of Mozart scholars have been telling us that his operas are all about sex, but you would have to travel far to encounter a Figaro with as little sexual charge and chemistry between the characters as this one.

It’s partly a problem of the casting. On paper, the prospects looked promising, at least vocally, but four of the five principal roles are disappointingly undersung; only Mark Stone’s Count has the athleticism and pheromonal charisma to bring his character to life on stage, but he’s severely taxed by his aria. Unfortunately, he’s working in a vacuum, with a dowdy Countess (Lisa Milne), tragically costumed by Niki Turner to look like the canon-bosomed Dame Clara Butt on her way to sing The Dream of Gerontius at the Proms when she makes her cathartic entrance in the finale.

His principal prey, Marie Arnet’s Susanna, is pretty and petite by comparison, but she’s also a prim, sexless bluestocking who looks a budding candidate for the Mrs Danvers Finishing School for Housekeepers. Arnet sings well, but wordlessly, for most of the evening. Victoria Simmonds, a charming Cherubino in the last, disastrous ENO Figaro six years ago, now looks mature for the role and sings charmlessly.

The biggest letdown, however, is the Figaro of Jonathan Lemalu, whose bass-baritone, once so promising, is a greying shadow of what it was when he was winning every prize going around the turn of the millennium. He’s a coarse actor, and you get no sense of a physical attraction between him and his intended bride. When the sexiest-looking (and sounding) woman on stage is Diana Montague’s Marcellina, Figaro is in deep trouble.

Maybe things will improve in January, when a different cast takes over. I won’t be holding my breath, though, because Fuchs’s take on this imperishable classic seems superficial and cosmetic, a Figaro obsessed with design tics (Yannis Thavoris’s art-deco-to- abstract sets are at least nice to look at) rather than offering any insights into Mozart’s comic genius. I didn’t laugh once, or care enough about any of the characters to cry.

There’s not much to laugh about, either, in Deborah Warner’s intense, gut-wrenching staging of Poulenc’s late-1950s monodrama La Voix humaine, which, in a harrowing 55 minutes, dissects what may be the last moments of a woman’s life as she abases herself on the phone to a lover who has left her. Emboldened by the success, two years ago, of the Eight Little Greats season — short operas given in double bills — Opera North and Warner elect to give Poulenc’s tragédie lyrique without a companion piece.

It works because the opera’s emotional rollercoaster is so exhausting to watch. Singing words by Cocteau, Poulenc’s heroine, Elle, plays out the obsessions and despair of the composer’s own amorous misadventures. At the time of composition, he had separated from his male lover, Lucien Roubert, and he referred to his last work for the stage as “a musical confession”, adding that “the protagonist is more or less myself”. One might have expected — or feared — that Warner would have chosen to make Elle a Lui, but she respects Poulenc’s musical rather than psychological intentions, drawing a performance of stomach- churning dramatic truthfulness from Joan Rodgers, a Poulenc specialist, who makes every word of Richard Stokes’s translation speak in the Leeds Grand.

In Tom Pye’s contemporary loft-apartment setting, Rodgers rolls around the floor clasping her telephone as if in a desperate lover’s final embrace. Of course, there are problems with the updating — the branch-line interruptions of the switchboard operator, the cuttings-off and wrong numbers are almost a thing of the past — but Rodgers acts out her agonies, swallowing tranquillisers and throwing up into her bidet with such raw truthfulness that one overlooks the essential anachronism. The layout of the apartment mirrors the protagonist’s emotional disarray, with the bathroom furniture demarcating the four walls of the room and her bed at the centre.

If Rodgers occasionally lacks the power to fill out Poulenc’s lyrical lines as sensuously as other famous interpreters, her commitment makes the denouement almost unbearable to watch in a pitiless staging. Even with Paul Watkins summoning sensuous sounds from the strings of the Opera North orchestra, this is not an evening for the faint-hearted, but it is compelling music-theatre.

La Voix humaine tours to Sadler’s Wells, EC1, Nov 22-24