While the Royal Ballet may be Britain's flagship ballet company, Rambert, founded by Polish-born Marie Rambert in 1926, is the oldest. Not that it's showing its age: 60-odd years after the company took a complete artistic swerve away from the classical repertory, and now run by Benoît Swan Pouffer, it remains the leader of the contemporary pack. And boy, did it look it on Wednesday evening at Sadler's Wells, celebrating its centenary with an absolute firecracker of a show.