Waiting for the show to begin, I was, I must say, slightly worried. The programme promised a celebration of “the innocent, natural and instinctive way in which young people can move, dance and behave” and described workshops where the 40 young dancers were encouraged to express themselves with complete freedom, so their improvisations could be shaped by choreographer Michael Keegan-Dolan and his assistants. I expected to see brilliance, but thought there were risks. It's so easy for people on the inside of a project like this to create something that will make little sense to those outside. My anxiety was soon swept away. In-Nocentes was wonderful. 

There's an introductory film, explaining how the National Youth Dance Company (NYDC) runs large 'experience workshops' for 16-18 year olds (older if you are disabled) before inviting some participants to work intensively during school and college holidays, for one year, to create “innovative and influential” dance with one of the Sadlers Wells associate choreographers. 

As the screen rises, the empty stage is edged with grey plastic chairs, one for each dancer, with the orchestra standing behind. Every dancer is dressed differently. Fingers click, hands tap and clap, feet stamp. From a series of questions and answers, a rhythm builds and individuals perform with an amazing diversity of personal expression, establishing dance for its own sake, before Max Richter’s rework of Vivaldi's music supports and shapes the flow and mood of intermingled stories and vignettes.

Everyone is visible throughout the hour-long piece, as it moves seamlessly through many scenes and emotions. Dancers leave the chairs to perform, in solos, duets, small groups and often all together. This is a strong ensemble piece. There are lots of extraordinarily good individual performances, where a dancer or group “throws down their moves”, but these are quickly picked up and developed by the company. We see brilliant hip-hop, acrobatics, sinuous jazz and graceful ballet, but nothing is ever left there: it is built into a strongly contemporary, disciplined and unified whole. There is a wealth of talent on stage, but the virtuosity is always a servant to the company, with sequences flowing into and out of exquisitely complex and beautiful ensemble sections, with phrases taken from one dancer’s particular skills or self-expression, cleverly developed through to powerful unison and canon for everyone.

There are so many memorable moments. The girl who sweeps her long hair round and round, making herself dizzy, until she invites four friends to join her for a few astonishing seconds when the shampoo-ad cliché suddenly becomes profound and lovely, or a breathtaking “shaking fit” from one dancer, is suddenly echoed by many more, in ways that do not seem possible. There are lots of laughs, from things as simple as the way someone bustles around and especially in the apparently artless reactions between the dancers. The company is so strong that it would be unfair and take too long to single out individuals.

Above all, the piece is rooted in individual personality. We often see the dancers smile, and smile at each other. This seems genuine and unforced, but that is equally true of the dance. The piece has come from these performers. They are expressing themselves, individually and collectively, and so are completely committed, fully inhabiting their movement. They are all expressive and happy to adopt others' phrases and techniques. Keegan-Dolan has used this to create a common dance language that requires very high levels of discipline to achieve yet feels natural, unstudied and apparently simple. It is human and so draws us in without needing to “explain”. More than once, the audience seems to give a conspiratorial giggle, as we recognise something we like very much in a personality or its expression.

 The South Bank Sinfonia, under Sian Edwards with Eugene Lee as solo violinist, gave Richter’s music more edge and brittleness in the faster sections, as well as more powerful dynamics than I have heard before, giving it a clarity and force which reflected the energy of the piece and gave more space to explore the richness of the slower movements. 

As the piece fell into darkness and silence, the audience stood and roared. Yes, there were lots of parents, siblings and friends there, but I felt privileged to have seen this. It was unique: Keegan-Dolan and his team have drawn from the gifts and commitment of these young dancers to create truly original, rich and extraordinary dance. It is on tour in June and July. See it.