Any adequate performance of Tristan und Isolde, and the first night of the Royal Opera’s production was at least that, leaves you wondering what to do with the rest of your life, as Wagner both feared and hoped it would. What Tristan does — one of the things — is to present an image of romantic love, in both its torments and its ecstasies, which makes everything else seem trivial; and at the same time to undercut that image by asserting the claims of ordinary life, but in the subtlest way. So, however swept away one is by the agonies of Tristan in Act III, and the raptures of the love music in Act II — and for the first time in decades the duet was given uncut, with the 12 minutes of music in which the lovers make their transition from the everyday world to their private one — there are these things to be remembered.Tristan dies in a state of delusion. So, separately, does Isolde. Earlier in Act III, when Tristan collapses after cursing the potion ‘which I myself have brewed’ his squire Kurwenal, thinking him dead, laments that he has fallen prey to ‘the world’s most beautiful illusion’. One of Wagner’s least celebrated qualities as an artist is his comprehensiveness, his matchless capacity to present the most glamorous images of what we imagine life could be, and to puncture them gently but decisively by slipping in the indocile realities that are what we have, finally, to live with.

Christof Loy’s production, here revived for the first time, is structured broadly along these lines, but severely underplays the heroism and is determinedly prosaic. Johannes Leiacker’s design is simple: a bare, slightly tilted stage, a kitchen chair, a massive deep purple curtain at the back, which is drawn at crucial points to reveal a wedding feast, or perhaps a stag night, all-male, tuxedos, lots of candles. There is no hint of the sea or of being onboard a ship. Loy argues in the programme book that that would be redundant, which is clearly absurd. So we must assume the guests are sufficiently far gone for their shouts of ‘Lower the anchor’ and so forth to be deluded, though so are Isolde and Brangäne in talking about being near to the Cornish coast. In fact, Act I is as firmly located onboard a boat as the first two acts of Siegfried are in a forest.

In Act II blowing out a candle seems a poor substitute for lowering the torch to indicate to Tristan that he can approach. And so on …this is one of those productions that will look as dated in 20 years as Wieland Wagner’s do now. But his are mainly old-fashioned because they were so beautiful, not a charge that anyone will level against this one.

The anti-heroism extends to the characters: Isolde initially wears a white wedding gown, but then changes into a black cocktail dress — and mysteriously at one stage she strips Brangäne of her outer clothes to show that she is wearing an identical dress. Tristan wears a suit once he’s shed his tux, and for Act III, which Wagner thought took place in the glare of the sun, outdoors, he sits on the kitchen chair, unbandaged despite frequent mentions of his wounds and of his ripping his bandages off in his delirium. Dressed as they are, and moving as they do — Isolde sits on Tristan’s lap for the duet, but mainly they wander independently round the stage — and at the crucial and unbearably lovely moments when Brangäne issues her warnings in Act II where she and Kurwenal are revealed to be having a straightforward non-airy-fairy screw behind the curtain, we seem to be in a domestic drama robbed of any metaphysical or heroic pretensions or connotations.

Despite all that, Nina Stemme as Isolde and Stephen Gould as Tristan give magnificent performances. Which is not to say that either of them is ideal. Stemme is rightly rated the leading Isolde of our time. She has a lovely and tireless voice, but lacks convincing low notes, is too purely a soprano, and could still make more of the text than she does. Gould is a stolid figure, a rudimentary actor, but his voice is powerful, he occasionally shows that he can sing softly, and his Act III sufferings are as vivid as they could be under the circumstances. Sarah Connolly and Iain Paterson are simply ideal as Brangäne and Kurwenal, both in the intelligence of their acting and in their meaning-charged singing. John Tomlinson, with very little voice left, makes an overwhelmingly moving Marke, the most passionate of all the characters. After a go-for-broke Prelude Antonio Pappano took Act I too slowly, every pause elongated, the ferocious exchanges strangely disjunct. In Act II he was a different conductor, from the magic of the departing horns onwards. Act III was thrilling but not profound. Yet the total impression of the performance was stunning, the audience absolutely still, the whole place humbled and exalted by the impact of transcendent genius.