If you'd stumbled across its staging of Mahler's Five Rückert Lieder, you could have been forgiven for fearing you'd entered a bizarre fashion show. A magnificent Town Hall ballroom; a catwalk in place; a sleazy cabaret feel; the audience tucked amid tables festooned with cocktail glasses of blue Curaçao; a parade of strangely dressed figures you might encounter at a Sally Bowles soirée.
Could this be Mahler, this bevy of black- and blue-clad figures resembling some weird scene out of Thomas Mann's Mario the Magician? Could a series of strange susurrations swelling to a crescendo - "Lord, watch over us when midnight comes" - have relevance to the rarefied world of lieder?
And then the singing voice enters: "Um Mitternacht" wells up from a few feet away. Right there, among you. A blue moon sheds its eerie night-light. First, there is the contralto Phyllis Cannan with an impassioned rendering of the midnight song. Then, after mutterings from embracing figures, there is "Ich atmet einen linden Duft!", sung by the baritone Thomas Guthrie. It is entrancing, enrapturing.
Streetwise's actors are not professionals. Instead, it draws on the performing gifts of the homeless. These people have worked at their art and, such was their discipline and concentration, you'd think they were seasoned aficionados.
Robert Thicknesse's pliant translations - the speaking was in English, the songs were in the original German - saw "Loving but beauty" ("Liebst du um Schonheit") shaped as a crooning pop song before Anna Dennis brought out the original's beguiling beauty. Meanwhile Mahler "himself" at his piano was assailed by a bevy of harridans.
What a muddle it might have looked without Soutra Gilmour's colour-coordinated costumes and Erica Whyman's tight direction. It all goes to show that starchy concert halls ain't all they're cracked up to be.