Some months ago, when I wrote a piece about an organisation called Sound on Screen, which is dedicated to celebrating and exploring music in film, I found it necessary to question whether they would find effective and innovative ways of bringing to the foreground music’s role as an integral element of the films we know and love.

I think, now, I have found an answer.

Opera, of course, has been using cinematography for ages and one takes its inclusion almost for granted. Daniele Abbado’s much (unfairly, I suggest) derided new sombre modern-dress Nabucco at Covent Garden (where it was a pleasure this week to witness the still tenory septuagenarian Plácido Domingo in the latest addition to his growing baritone repertoire, as well as the smashing Royal Opera chorus in Verdi’s ‘chorus opera’ par excellence) makes judicious use of film in the backdrops.

But it was at the Barbican that I witnessed a truly effective fusion of art forms to create what I can best describe as both an opera and a film, where the whole film-opera is a dramatic conception: in theory at least, nothing is included simply to show it can be done. English National Opera’s world premiere of Dutch composer Michel van der Aa’s Sunken Garden is a genuine multi-media piece of art, embracing 3D cinema drama. Is it an opera with film or a film with music? Either way, Sound on Screen might want to embrace the concept because it achieves what they set out to do. And it does so because film and music are conceived together as equally significant partners and van der Aa is in control of both.

Co-commissioned by ENO and the Barbican, Luminato Festival and Opéra National de Lyon, Sunken Garden, with the ENO Orchestra in the Barbican pit, uses three live singers on the Barbican Theatre stage – plus two more, these singing holograms, in the 3D film world of the mystical garden which, accessed through a door in the pillar of a flyover, turns out to be a sort of limbo or Purgatory in the dusk between life and death. And when you’re in limbo you need your 3D glasses to get your remarkable bearings.

But I’m getting ahead of myself. The first half of the work, before we enter the sunken garden, takes place both on stage and in the familiar two-dimensional world of film, where the mysterious disappearance first of an IT contractor and then of his girlfriend is explored by way of filmed documentary-style interviews (spoken, not sung – some lovely acting it must be said) with those who were mixed up in their lives. The libretto is the work of novelist David Mitchell, of Cloud Atlas fame, who, speaking of the garden itself – ‘a dusk between life and death’ – says: ‘In this other realm Michel saw a way to embed the 3D film element into the DNA of an opera, as opposed to it being an add-on…Our model here was the use of Technicolor in The Wizard of Oz, where the altered perception – the colour – is heralded by a different state, when Dorothy leaves her cabin and steps into Oz. Our libretto, then, would require another reality “sunken” into it.’ The sunken garden, if you like, takes us into a different dimension.

Van der Aa, who directed the production, including the film, as well as composing the music, took the decision not to have his characters interchange between stage and film mediums. ‘With 3D,’ he says, ‘the live singers can be integrated inside the visual envelope in a way that wasn’t possible before.’ When you watch the garden scenes through the glasses the integration between live singer and 3D hologram singers, replete with special effects, on screen is seamless. The effects are worthy of the 3D medium and there is an equivalent integration of sound from the theatre pit and the singers on stage with the film-generated sound. Always interested in the medium of film, van der Aa majored at university in musical engineering rather than music and got to know the ins and and outs of the recording studio at first hand.

It all shows. This is a clever as well as complex piece of work, with a fiendishly complicated plot, and Roderick Williams, Katherine Manley and Claron McFadden, the three well-chosen on-stage singers, deliver it with aplomb. This is real drama and it works dramatically. The mystery is as complex as TV film noir. The spoken interviews work as film and the 3D (which hitherto I’ve managed to avoid!) successfully drew me right in to the sunken garden.

Crucially, Sunken Garden works as opera, with van der Aa’s fusion of musical styles matching the fusion of mediums, and conductor André de Ridder and the ENO Orchestra proving themselves a match for their unconventional surroundings.

The opera runs at the Barbican until Saturday and will subsequently be seen abroad. This is truly ‘Sound on Screen’ and it’s worth catching in the theatre. But I do find it curious that Radio 3 is to record tonight’s performance [Thursday] for future transmission. Should we expect a film-opera (or an opera-film) to work without the film?

I don’t claim to know the answer – opera is written for the theatre, yet on CD (indeed on LPs) it can still pack an enormous punch. But this work was conceived as a whole, so why should we expect the music to stand on its own?

If the visual element of Sunken Garden is crucial to the impact, surely removing some of its limbs will take away its raison d’être. If Sunken Garden is anything like as effective on the radio van der Aa will truly have written a remarkable opera.