A wicked deception is sprung in the opening moments of this New York-originated concert staging of Stephen Sondheim and Hugh Wheeler’s Sweeney Todd. The English National Opera orchestra, liberated from the pit, is duly assembled on stage at the London Coliseum; flower arrangements and a Steinway grand add to the formality, and right on cue the conductor and cast, suitably attired in evening wear and with scores in hand, take their places behind a line of music stands. The applause dies and Bryn Terfel turns to the conductor, clears his throat and nods. The whirring ostinato introducing ‘The Ballad of Sweeney Todd’ begins — furtively — and Sweeney, of course, has the first word.

It’s a little like flinging down the proverbial gauntlet, dramatically speaking, but what we’re not expecting (spoiler alert) is that he — the demon barber of Fleet Street — should fling down his score, too. In a chain reaction of civil disobedience the promised ‘concert performance’ is abandoned and anarchy ensues until the flowers are strewn across the stage, the plush velvet drapes ripped down, the piano upended, and the temple of art is unceremoniously transformed into an urban jungle with banners of Banksy-like graffiti and what will become the leitmotif for this entire saga of revenge — a bloody handprint.

So what director Lonny Price offers here has developed from its origins some years back into quite a bit more than just a semi-staging. Price played Charley Kringas in the original production of Sondheim’s Merrily We Roll Along so he knows how the master’s music rolls and putting the orchestra at the centre of the action, indeed evolving many of the props from musical instruments, keeps this most Gothic of scores quite literally at the foreground of the evening. The orchestral contributions — so elegantly and keenly attended by David Charles Abell — roar in their most Bernard Herrmannesque manner while a huge ensemble of ghostly figures implore their demon barber ‘swing your razor high, Sweeney’. Miked to within an inch of its life, it’s quite an intimidating noise.

But this Sweeney is writ large, larger, largest — and what you gain in Grand Guignol gestures you lose in sharpness and a darker subtlety. It’s broad, very broad, and it all seems to have taken its cue from the man in the title role, Bryn Terfel, whose booming bass-baritone plumbs the ‘hole in the world like a great black pit’ with cavernous authority but a jot too much pantomimic declamation. Paradoxically, what thrills in his performance are not so much the big moments but the quietly dangerous ones — the icy, rasping, hoarse whispers, the slow burns. Oddly his big set piece ‘Epiphany’ felt somewhat muted on account of his remoteness from the audience. Price should have brought him into our midst sooner. His hectoring invitation to get each and every male in the audience into his barber’s chair is one of the great ‘be afraid, be very afraid’ moments in all musical theatre but somehow we didn’t feel threatened. What a neat idea, though, to make his barber’s chair a tip-up theatre seat. Now that made us feel vulnerable.

And, of course, one of the great rug-pulls in musical theatre occurs when high melodrama is undercut by low music hall at the point Emma Thompson’s rip-roaring Mrs Lovett comes up with her waste-not-want-not solution to what they might put in her pies — ‘A Little Priest’. Her timing and natural comedic talents made her something to savour throughout, though again I’d love the opportunity to see her fine-tune the role in a smaller venue.

Casting, though, was pretty exemplary, focusing on prime musical theatre talent — no weak links at all — and it was good to welcome three-time Olivier winner Philip Quast back to our shores with his odiously imposing Judge Turpin. He and Terfel were so well matched in the tantalisingly suspenseful ‘Pretty Women’, where music and razor tease and caress in anticipation of the most satisfying cut of all.