Luis Buñuel would have loved the delicious irony of this: an opera critic dissecting the finer points of a Covent Garden performance of an opera based on his 1962 El Angel Exterminador – a film whose essence is the merciless lampooning of the mores of precisely the sort of upper class people he would have expected to find in an opera house.

The basics of the film are straightforward and are rendered with surprising fidelity by Thomas Adès and librettist/director Tom Cairns. As the über-posh Edmundo and Lucía de Nobile welcome their well-heeled guests to an elegant dinner party, all but one of the servants inexplicably leave. As the evening draws to a close, an unknown force prevents the guests from departing: they don their coats, say their goodbyes and approach the exit – but no-one is actually capable of leaving the room. Events then take their inevitable course as food and water run out and underlying nature breaks through the mask of polite gentility.

Not only do Adès and Cairns maintain the claustrophobic atmosphere and the key flow of Buñuel’s narrative, but they also preserve many of the movie’s iconic moments – the repeated entrance of the guests (think Groundhog Day), the hallucinations of a disembodied hand, the appearance of a bear and three sheep (there’s a gloriously dark moment late in Act 3 when the starving guests set eyes on the sheep and realise that what they’re looking at is dinner). Also preserved are some moments that are memorable but are, quite frankly, Buñuel self-indulgences, such as the smashing for firewood of a cello (added as the result of a row with Pablo Casals).

The pace and mood of Adès’s score are constantly shifting and he proves adept at a dozen different genres, with effective pastiche of anything from romantic piano music to the flamenco-laden sounds of a Spanish fiesta. Some of his writing is very virtuosic indeed. With so many different soundscapes, I suppose it’s inevitable that I disliked some of them, most particularly the way Adès writes for high soprano voice. As the opera singer Leticia (nicknamed “the Valkyrie”), Audrey Luna carried the lion’s share of the high register pyrotechnics, helped somewhat lower in the tessitura by Amanda Echalaz’s Lucía. It’s all very impressive, but I found the sound unpleasantly brittle and it’s the one area where my sense of humour failed me in an opera that is extremely funny for most of its length. I was happier when Adès turned his hand to romantic sweetness in the shape of a stunning aria by Christine Rice’s Blanca and sevaral gorgeous duets between Ed Lyon and Sophie Bevan as the doomed lovers Eduardo and Beatriz. I also didn’t get on too well with the default “not much is happening so I’m gradually building the tension” music in Acts 1 and 2, where I struggled to find coherence, in contrast to the music after the interval, when events become more extreme and the different musical passages are more clearly demarcated.

As he so often does, Sir John Tomlinson (as the Doctor, the voice of rationality in the party) stood out from the pack of male voices: his physical presence on stage is imposing (not just because of physical stature) and his voice draws the attention magnetically. While there were other strong male vocal performances, most notably from Charles Workman as Eduardo and Morgan Moody as the butler Julio, I can’t name check them all, not least because of a staging problem: with a room full of people who can’t get out, everyone is on stage all the time. All the men are wearing similar formal dinner dress and – admittedly following the example of the movie – lighting is subdued and mostly from a low angle, meaning that from a faraway seat, it was often extremely difficult to tell who was singing (with the obvious exceptions of Tomlinson and countertenor Iestyn Davies).

Generally, however, Cairns’ direction was exemplary, getting a large cast (there are twelve guests as well as Edmundo, Lucía and Julio) to execute complex movements and seem completely natural, as well as staying in character for over an hour at a time. Hildegard Bechtler’s set is generally spare, but contains just enough detail to convey the opulent atmosphere while remaining serviceable for the few scenes set in the street outside the mansion.

The key message gets through: utter derision at the sense of entitlement of these over-privileged, self-righteous prigs. The pivotal moment is when the roasted sheep is finally being served to the starving guests: you might have expected relief and gratitude, but no, there are merely complaints about the meat being overcooked and lacking salt. And the happy ending – sweetness and light as the ordeal ends – is thoroughly subverted by an extraordinary Latin mass Lux perpetua and the arrival of armed soldiers – the Franco regime, we assume. Whether you be Buñuel fan or no, this is gripping stuff.