In the operas of Benjamin Britten, it's often the orchestra that communicates the deepest truths.

The famous Sea Interludes in Peter Grimes set the scenes but also distil the drama's brooding atmosphere. Rising orchestral harmonies ratchet up tension in The Turn of the Screw until it's about ready to snap. In Billy Budd, the tender meeting between young Billy and Captain Vere happens behind closed doors while the orchestra is left to feed our imaginations. Sometimes instrumental music is able to express what words cannot.

From the very first notes of A Midsummer Night's Dream, Britten's shifting, shimmering orchestra spirits us away to the nocturnal mischief of a troubled fairy kingdom. Shakespeare's original splits the action fairly equally between the Athenian lovers, the troop of bumbling rustic actors and the enchanted forest domain of Oberon and Tytania. When Britten set to making an opera out of the play in 1959, he declared Shakespeare's trisection "especially exciting" and used tricks of musical form and colour to keep the distinctions clear. His humans sing in full operatic voices with warm, rich accompaniment. His rustics parody 19th and 20th century operatic clichés (Verdi and Schoenberg each get a few digs) to the sounds of honking lower winds and brass. But it's his fairies who really draw us in, their voices floating ethereally above twinkling keyboards and harps. Oberon is a countertenor – one of the only lead roles that Britten did not write for his partner, tenor Peter Pears – while the chorus of fairies is sung by unbroken treble voices. Puck is an acrobatic sprite who never keeps still long enough to sing at all.

To mark Britten's 100th birthday year, Scottish Opera and the Royal Conservatoire of Scotland turn their combined efforts to A Midsummer Night's Dream. For their eighth annual collaboration – in which students and professionals work side-by-side – they've chosen a production of Britten's opera by director Olivia Fuchs, first seen at the Royal Opera House in 2005. It's a sleek-looking number. Nikki Turner's set is a minimalist midnight blue lit by cold neon strips, while video projections pick out images from the text – snakes, owls, dewdrops melting into a human eye. Nothing is spelled out in this production: if Britten's opera seeks the murky, ambiguous corners of Shakespeare's play, Fuchs lingers in those corners further still. And with a sparse stage to play with, the dramatic action relies on the orchestra, the singing and the physicality of the performers. And that's where Jami Quarrell comes in.

Quarrell, a Glasgow-born actor and aerial artist, has played Puck in every outing of Fuchs's production. Reviews of the 2005 run described him as "gloriously acrobatic'" and "the best actor by a mile" – he's the fulcrum of the production, yet he hardly sings a note. Between rehearsals last week, he explained his evolution as a performer and his approach to Britten's most devious fairy.

After starting out in drama workshops at the now-defunct Strathclyde Arts Centre, Quarrell found himself increasingly drawn to physical roles and headed south to circus school in London. He made his niche on the corde lisse (vertical rope work) and moved to Paris to study with a 60-year-old Russian flying trapeze artist. Nowadays he works mostly with dance and physical theatre companies, but collaborates with opera "whenever there's a role that requires a blend of acting and heightened physicality," he says."In this production Olivia demands a high level of physicality from all of the singers. She focuses in on the magical physicality of the fairy world. I've really enjoyed sharing my skills with the cast – not just the high-octane physical stuff, but also the finer points of presenting a character through movement. These guys are the new generation of opera singers: young, fit and up for anything."

Puck himself is a tricksy character, "a go-between between the humans and the fairy king and queen", Quarrell explains. "I'm a bit of an eternal teenager or hooligan. Then there's the relationship between me and Oberon – the homoeroticism, the sense that we're inextricably linked. We're two sides to one being. Oberon's the patriarchal authority side who needs to keep it all together, and Puck is the side that wants to create mischief. Remember the animal daemons in Philip Pulman's Northern Lights trilogy? That's the relationship we're going for in this production."

So Puck is the unseen, tethered side of Oberon, able to zoom around the earth in the blink of an eye but ready to snap back to his master's side like a boomerang. "I want Oberon's attention constantly, and I vie for it with Tytania. I'm happy to create complete havoc by making her fall in love with an ass, then when things return to order at the end of the opera I'm in a big old sulk about it. It's fun."

There's an intriguing sense of amorality to Puck: he's not benign or malevolent as such– those are human attributes – but he doesn't understand the upset wreaked by his mischief. "He's like an animal, like a kitten playing with a mouse. He's reacting to whatever stimulates his imagination. Oberon has more human responsibilities at heart."

Quarrell warns that anyone who is attached to seeing Midsummer Night's Dream "with a bunch of pretty trees on the stage" shouldn't bother coming to this production: Fuchs's dark and murky setting is, as one London critic put it, the perfect Midsummer Night's Dream for midwinter. "What Olivia and Nikki have created is the interior of the human psyche," says Quarrell. "The forest is the inside of the mind."

The centrepiece of the staging is a massive midnight blue armchair in which all of the cast takes turns sitting. We're left with no real conclusion as to who is doing the dreaming or who is just a figment of fantasy, but as Puck reminds us before we go: if these shadows have offended, think but this, and all is mended: that you have but slumbered here, while these visions did appear; and this weak and idle theme, no more yielding but a dream. "Whatever you take from this show," says Quarrell, "it's ultimately a reflection of yourself. Britten took all the impulses of human love, frailty and jealousy and orchestrated them in his enchanted forest world. So our midnight blue set is just a screen on to which you can project your own deepest thoughts and feelings."

A Midsummer Night's Dream is at the Theatre Royal, Glasgow, this Friday and Saturday; at Eden Court, Inverness, on January 29 and at the King's Theatre, Edinburgh, on January 31 and February 1.