George Piper Dances/Ballet Boyz, Queen Elizabeth Hall, London

Christopher Wheeldon's Mesmerics is a full company work. Since the company is George Piper Dances, the ambitious but tiny group founded by William Trevitt and Michael Nunn, aka the Ballet Boyz, that's still only five dancers. Wheeldon's sense of space gives them the impact of a full corps de ballet, using the full depth of the stage in mirrored patterns.

Trevitt and Nunn have a gift for unexpected impact. They've used their Ballet Boyz TV diaries to pull in new audiences, and the flexibility of their small company to wheedle new works from some of the world's busiest choreographers.

Mesmerics, new last autumn, is their best commission to date. It's also their most classical. Trevitt, a dancer of lean, clear lines, has always been the Boyz' classicist. Here, the whole company pick up that sharpness. The steps are sinuous, flowing around the Philip Glass score for strings, but they have a smooth balletic rigour. Jumps are taut, and swung arms have a scything force.

Wheeldon's floor patterns are gorgeous. Dancers sweep in on diagonals, retreat, reappear from different angles. Canons of movement travel forward, then backward along a line of dancers who change direction or position without breaking the design. Then they burst out altogether, flowing across the stage in new shapes.

The opening solos are less compelling. The dancers spend too much time bent double, and need more rhythmic variety. The dance comes into focus when Wheeldon starts layering solos, setting one dancer off against another. In Michael Hulls' soft lighting, fast movement leaves a glowing trail, emphasising the circling arms.

William Forsythe has been at the heart of George Piper Dances' repertoire from the beginning. They dance his choreography with unusual warmth, giving a touch of humanity to the forced, off-balance movement. Last year, Forsythe reworked his Approximate Sonata I, IV for the company, effectively giving them a new ballet. It's a standard Forsythe duet, with electronic music, a little philosophising and a lot of straining limbs. Trevitt walks along a side line, pulling faces and responding to offstage directions. Then there's a solo: knocked knees, rotated shoulders, loping walks. Monica Zamora joins him for a yanking duet. He's cheerful, she's elegantly contained, and they both dance with athletic power. Forsythe's choreography still looks wrenchingly dogged.

Russell Maliphant made Broken Fall for the Boyz and Sylvie Guillem. Revived with Oxana Panchenko, it's a more evenly balanced work. The final solo no longer looks like a crust thrown to fans of Guillem's leg extensions. But it's still an unfocused work. Barry Adamson's music drifts; the dancers meander through catches and throws. But they work Maliphant's soft-grained steps well, with sure phrasing and a sense of comradeship. This is a confident, close-knit company, not just an ambitious one.