My favourite moment in Blush is when one of Wim Vandekeybus’s ten-strong cast throws crumbs at the front row of the Theatre Royal, and footage of snorting, feeding pigs suddenly appears on a giant screen at the back of the stage. Are we supposed to feel insulted, being compared to pigs? My guess is that Vandekeybus, whose Ultima Vez company is now on its 15th show, doesn’t mind, as long as there is an involuntary reaction of some description, A blush, in other words.

This is a show about the way people react to things. It begins with a man, who has just had sex but doesn’t know it because he was asleep, pointing at members of the audience and asking provocative questions ("do you swallow?" etc). Then a woman lists all the ways she has provoked physical or emotional reactions in herself: punching her fist through a window; watching a mosquito suck blood from her arm. These things, she says mournfully, she will never do again. We meet her again later, at which point she seems to be dead or dying. At the funeral, two men have a row about love; one says it is a beautiful, poetic miracle, the other says it’s a chemical reaction in the brain. They fight, and one of them ends up naked, screaming "Love or death!"

None of this does justice to Blush. A terrific fusion of theatre, music, film and dance, it assaults you with imagery, and almost every image is gorgeous and spectacularly choreographed. Meaning keeps hovering into view and then flapping off again; forced to guess, I’d say it’s about how our instincts often become so raw and savage it’s difficult to distinguish us from animals.

In every dance sequence there’s an undercurrent of violence. Out on the street afterwards, a woman said: "What was all that about?" Fair point. Looks fabulous though. See it tonight if you can.

4 stars (out of five)