William Forsythe has been called a lot of things in his four decades as a dancemaker: wilful provocateur, ‘pretentious as hell’, even ballet’s Antichrist. But nothing, he claims, to warrant US government officials showing up, unannounced, at his door and threatening him with arrest.

Had he been reported by an angry dance purist, perhaps? After all, this is the choreographer who has done more than any other to push the limits of what ballet can be, the great forward-thinker hailed for his athletic, sometimes bewildering, deconstructions of an art form that goes back centuries.