The 'Glory' pop icon heads across the pond to perform her greatest hits and new tracks from her latest studio album as part of the Apple Music Festival. For all her hyper-sexuality, Britney Spears still moves like a phoenix, so her dozen dancers did the more taxing legwork, leaving her as the gyrating calm in the center of the frenzied hurricane. This was a riot of sound, color and movement. More important still, from first to last it was fabulous fun.