George Piper Dances, The Roundhouse, London

The Royal Ballet renegades William Trevitt and Michael Nunn, aka the group George Piper Dances, deserve to succeed if only because they aim to put a fresh spin on ballet and look as if they might just do it. They possess the supreme advantage of their own self-generated publicity machine, thanks to their cult Channel 4 video diaries, Ballet Boyz, which revealed them as much Bovver as Ballet Boyz, capable of challenging ballet's effete stereotypes and showing an alternative to a wider public.

The further instalment they are planning should come in useful, but first they need to shake up their programming. This, for their launch tour, is a dance sandwich with delicious bread and a dull filling, the whole thing resting in an untidy bed of limp lettuce.

The lettuce is the video footage linking the pieces, which looks thrown together in a final-hour panic. (The rough conversion of the Roundhouse into a theatre probably didn't help to soothe nerves either.) The bread is the opening and closing pieces, which would on their own have made a brilliant, if frugal, double bill. Steptext, William Forsythe's teasing overturning of theatre conventions, gets a satisfying performance that seems to uncover a layer of drama, marred only slightly by Matthew Hart's over-projection. But Oxana Panchenko doesn't need to over-project; she is a spectacular moving Giacometti sculpture, arcing long, tensile legs with exquisite deliberation in her pas de deux with Nunn.

Russell Maliphant's Critical Mass is another tour de force, a male partnering duet poised between grappling conflict and brotherly tenderness. It accumulates repeated rhythmic moves while varying their texture and emotional charge, and Nunn and Trevitt dance with seamless perfection. You hope it never ends, transfixed by its sweeping originality and accomplishment.

Nunn and Trevitt can perform, make TV and charm our socks off, but so far their choreographic efforts seem disposable. The trio of eccentric characters in Trevitt's Tangoid need surer, more vivid delineation to avoid being pointless. Moments of Plastic Jubilation, created by Nunn and Trevitt, is backed by video projections, some live, which don't add up to anything, while its dances for the company never rise above unambitious shape-making.

That leaves Paul Lightfoot's more skilled Sigue, which ends with white powder cascading on to the prostrate bodies of Panchenko and Trevitt. The Independent on Sunday critic Jenny Gilbert's theory that this is the ash of death is inspired; the idea gives a sudden logic to the oblique preceding images of this intense duet to Chopin.

There is definitely room for contemporary chamber ballet that can reach a young or adventurous audience. In December George Piper Dances return to London with a new piece by Charles Linehan. If that replaces the weaknesses here, they should have a winning formula.

Touring to 2 Dec, then at the Queen Elizabeth Hall, London SE1, 4-6 Dec (020-7960 4242)