In the Royal Opera’s new production of Così fan tutte, all four lovers are young and attractive, and all four sang their parts with excellence. But it wasn’t enough to rescue an evening made tedious by leisurely tempi and a staging by Jan Philipp Gloger that seemed far too clever for its own good.

Semyon Bychkov is a conductor who gets more accurate performances from the Royal Opera orchestra than anyone except Pappano, and last night was no exception: playing was crisp, precisely together and error-free. But the tempi were leaden. This performance ran for three hours and five minutes, and I felt every one of them: Mozart’s music trudged where it should have fizzed.

Within those confines, the quartet of lovers all impressed, especially in their set piece arias. Corinne Winters has a very pretty soprano voice, with warmth, real character and not a hint of wobble: her Act I aria “Come scoglio” (Like a rock) applied rather more correctly to Winters’ singing technique than to Fiordiligi’s constancy. Angela Brower’s Dorabella matched her nicely in duets and sang a vivacious “Smanie implacabili”.

Tenor Daniel Behle made an excellent impression in his Royal Opera debut: his voice is bright and highly intelligible, and he has a good reserve of strength for Ferrando’s big arias. As Guglielmo, bass-baritone Alessio Arduini gave a strong, rounded baritone throughout.

But very little of this fine singing translated itself into charm: all the performances seemed terribly earnest – which is almost certainly not an accident. Gloger’s staging has a clear intent: to take everyone in the audience who is unfaithful, or has fantasised about being unfaithful (which he assumes to be everyone) and make them feel uncomfortable. Gloger is hammering home the message that “this is an opera about you”: it’s classic Brechtian Verfremdungseffekt.

Gloger achieves this by taking every opportunity to blur the boundaries between the audience, the characters’ “real” world and their imaginations. In the overture, we are treated to a curtain call by singers in Mozart-era frock coats and wigs, who then turn out not to be the real singers at all – the four lovers, in modern dress, are in the aisles of the stalls, from which Ferrando and Guglielmo sing their opening number. The two “foreigners” appear first as barflies (Despina is a cocktail barmaid rather than a maid, with the chocolate for the sisters’ breakfast being of a distinctly alcoholic nature), then as turbaned figures of orientalist fantasy. It’s made very clear to us that Fiordiligi and Dorabella are in no doubt whatsoever about the Albanians’ true identities. There are swathes of “play-within-a-play” concepts, without any coherent connection that I could discern. The giant COSI FAN TUTTE neon sign gets bulbs unscrewed to transform it into COSI FAN TUTTI, to disabuse any Italian-speaking men in the audience of any possible feeling that it’s only the women who are being targeted.

There are two problems with all this. The first is that the action is constantly fighting against the libretto rather than working with it. To pull this off needs very skilful acting direction – it has to be communicated visibly to the audience that the singers know perfectly well that what they’re singing doesn’t match what they’re doing, otherwise it’s just confusing – and I didn’t feel that this was in evidence. The second is that it robs Così fan tutte of all charm, which is most of the work's virtue.

Sabina Puértolas played Despina as a genuinely nasty piece of work rather than an airy good time girl. Johannes Martin Kränzle delivered Don Alfonso’s self-congratulations as targeted point-scoring rather than harmless fun. With all this added to the plethora of serious points and Bychkov’s extremely slow tempi, it felt like a very long evening.