Last week was bookended by opera. On Monday I sent composer Philip Sunderland the second full draft of the libretto for our March 2016 collaboration The Glass Knight, and on Friday I experienced the closest thing to secular transfiguration at the opening night of Longborough Festival Opera‘s magnificent Tristan und Isolde.

To take these in order: Saffron Hall (a gift from an anonymous philanthropist to his local town, and to my knowledge the only world-class concert venue in the grounds of a UK state school) have commissioned a new opera based on the medieval legend of the Saffron Walden basilisk, involving over 300 children from local schools alongside professional singers and musicians. Philip and I have been playing around with the outline story for the past three years, but with performances now confirmed for March 9th-12th 2016 we’re busy turning ideas into singable reality.

Writing an opera libretto is subtly and profoundly different from writing poems: where a poem has to supply its own verbal harmony, a libretto needs to be able to fade into the background and allow the music to take over; technical tricks that would dazzle in a poem simply get in the composer’s way, tugging lines in the wrong direction or drawing too much attention to themselves. At the same time, a libretto needs to convey the essentials of character and plot with a ruthless economy, and needs to contain enough real poetry to fire the composer’s – and the audience’s – imagination.

The Glass Knight is about the way we tell stories and why myths matter. It overlays four different historical periods while multiple characters from the town’s past act out their versions of the legend, none of which (the audience comes to realise) tells the whole truth. If that sounds like stretching material for a children’s opera, one of the joys of this project has been supercharging those aspects of theatre that children instinctively understand better than adults (the cognoscenti leaving the latest avant garde sensation might mutter knowingly about metatheatre and the fourth wall, but your average eight year old yelling “he’s behind you!” at a pantomime not only understands these concepts but doesn’t find them strange enough to need special names).

I’ll post more about The Glass Knight as things develop, but with 9 months to go until first performance I’m already filling my working day with a backdrop of sound files as Philip works through one fantastic musical idea after another. This is going to be fun.

Wagner would have had no need of sound files or concerns about his librettist getting in the way of the music, although (as with the Ring) he called the text for Tristan und Isolde a “poem” rather than “libretto”. Nor did he have much time for “opera” in his later work, preferring “music drama”, “action” or “total artwork”. All this semantic precision might sound like special pleading if the works themselves were not so powerfully different from anything else in the repertoire. For many people (me included), Tristan, Parsifal and the Ring are among the supreme achievements of the human imagination.

And what better place to stage a transcendent, dangerously-powerful work of art than in a converted cowshed on the outskirts of a Cotswold village? Longborough Festival Opera has repeatedly pulled off the remarkable feat of staging Wagner’s most complex and demanding works in a privately-built theatre with a fraction of the budget of a major opera house production. Yes, the idyllic surroundings and champagne-with-a-view help to make it special, but there’s no getting away from the enormity of the achievement and the sheer quality of the performances.

Tristan is a dangerous magic: five hours of surrender to the unconscious, a sublime mix of Schopenhauer death-wish and the tectonic collision of Romanticism and Modernism. It’s no accident that this is the only work of art Eliot quotes twice in The Waste Land. Over time, the sound-world becomes a kind of operant conditioning for emotions we can neither name nor express.

It has a lot in common with religious ritual, and as such is substantively different when encountered first-hand. My 21-year-old self wandered the streets of Oxford for several hours in shock after WNO’s touring production passed through town; and I can still remember a friend a year earlier wowing an impromptu audience in the college chapel with a rendition of Isolde’s death-prayer (commonly called the liebestod, although Wagner himself reserved that term for the orchestral concert version in conjunction with the Act 1 prelude and preferred “transfiguration” for the finale).

Everyone who loves Wagner carries around an ideal Tristan that no real-world version can live up to. But for me the new Longborough production comes painfully close.

Carmen Jakobi’s direction, Kimie Nakano’s set, Ben Ormerod’s lighting and Didy Veldman’s choreography combine to produce a perfect physical counterpart to the music. Jakobi has taken some bold risks, most notably introducing dancers Katie Lusby and Mbulelo Ndabeni as the staged embodiments of Jungian archetypes from the protagonists’ individual or shared unconscious. But these risks pay off brilliantly: the concept doesn’t distract from the music but amplifies it. When Ndabeni appeared behind the dying Tristan as his unassimilated shadow I saw a collective shudder run through the audience.

The singing and playing (and, dearest to Wagner himself, the acting) were first-rate throughout. Peter Wedd gives real depth to Tristan, turning Act 3 into a mesmerising journey into the personal unconscious and autobiographical memory. But the evening belonged to Rachel Nicholls as Isolde: magnetic and thrilling throughout (someone walked over my grave at the “death-devoted heart” motif in Act 1), the closing death-prayer was beyond brilliant. The audience was on its feet without any sign of conscious intent; nobody even tried to hold back the tears; we knew we had just experienced something very special indeed.

Wagner, poet-librettist as well as composer, did not choose his terms lightly: transfiguration is about the only word that can express it.