Should we watch the second act of Tristan und Isolde (without the first or the third)?

There aren’t many operas from which you can extract a single act and make a concert of it, in fact I can’t think of any except ones by Wagner. I’ve been to Act I of Die Walküre, Act III of Die Meistersinger¸ Act III of Parsifal at the Proms, Act II of Lohengrin, and several times to Act II of Tristan und Isolde. It’s not that Wagner’s acts tend to be longer than anyone else’s, they don’t: Handel’s often last as long, so do Rossini’s. It’s rather that some of Wagner’s greatest acts are so rich in musical and dramatic material, so perfectly shaped and have so powerful an impact, quite apart from being extremely demanding of their performers, that it is a luxury to be able to give them all you’ve got and not have to look forward, after an interval of chat and drink, to another draining 80 minutes.

Act II of Tristan would seem to be, perhaps more than any of the others, an ideal case. In the past three or four years we’ve had it under Rattle at the Proms, under Jurowski, and now, at the Barbican, coupled with Schubert’s Unfinished Symphony, under Daniel Harding. On each occasion I have had mixed feelings, up to a point independently of the merits or otherwise of the performance. The one I responded to most ardently was the Prom under Simon Rattle, where the tenor was virtually voiceless, the conducting electrifying.

I suppose that the reason that Act II is thought to be so excerptable is that it has the love duet, which apparently is most people’s favourite part of the work. Yet it is the part that is hardest to bring off. It’s not only a matter of its immense proportions — about 40 minutes, if it doesn’t have the heinous cut that is still common, ten minutes of inspired and indispensable music — but of the series of climaxes, which have to be impeccably scaled if it’s not to turn into a shapeless though exciting mess.