Is glamour essential to the circus? The seven members of Canada's Les 7 Doigts think not. In a drastic revolt against the elaborate costumes and outr sets purveyed by their former employer Cirque du Soleil, this troupe appear in simple white cotton underwear on a stage that looks like an alternative pad for TV's Friends after a plot downturn puts them all on the dole. In this show there's no need for entrances cued by drum rolls, since the entire cast is on view at all times, lolling on the shabby sofas, mooching about setting props or lying in the bathtub till it's their turn to shine. No need either for a fancy rock band when you have the one-man-band DJ Pocket, a virtuoso of scratching, beatboxing and tuneful improvised ululating, to crank up the atmosphere.
You notice that Loft, the first circus show to visit the restored Roundhouse, even rejects the traditional in-the-round set-up, going to the trouble of constructing a square platform against a wall of the circular former engine shed. They have their reasons. At one point an entire family of latecomers are ushered to their seats having been shown in to their red-faced amazement from the foyer via the door of the stage-kitchen fridge.
Essentially, though, these are circus acts everyone will recognise: girls with nice legs doing things in the air, men with visible musculature doing things on and off the ground, a little-and-large duo who clown about on this occasion wielding diabolos.
Can a beach game involving two sticks and a length of string make theatre? Seeing is believing, as wiry Sebastien (a dead-ringer for Ben Stiller) and hulking Patrick dandle their diabolos like babes in arms, walk them like puppies, knit with the sticks, truss their own torsos like turkeys for roasting and finally, in a release of tension that brings the house down, combine catching the flying plastic sputnik with a standing backflip on a man's shoulders.
What all the acts have in common is a basic honesty. There are no tricks, nor, for that matter, safety nets. However impressive the manoeuvre Shana, in bare legs and schoolgirl plaits, hanging 20ft up by virtue of a steely instep, Faon threatening to render her body in twain as she holds mid-air splits yanked by chains, Gypsy (what names!) catching a lethal-looking kitchen knife in the crease at the back of her knee it's clearly all for real.
But like all the best experiments, Loft doesn't win every point. The peripheral stage business is sometimes inspired, but just as often looks messy and arbitrary. There's an awkward moment when Samuel, the Nureyev-lookalike who does balletic handstand variations on revolving poles, reads a terrible poem about solitude. We're meant to think it's terrible, but that doesn't make it any less odd.
And yet the highs a trapezist spinning wildly to the climax of a Coldplay ballad, the sheer rubbery invention of the physical clowning, and the realisation that a summons to one and all to climb on stage at the end and eat apple pie is genuine make this one experiment I will gladly try again.
Roundhouse, NW1 (0870 389 1846) to 30 December