The Judas Tree was the last ballet created by Sir Kenneth MacMillan before he died – and it is his darkest. The plot is an allegory of Christ's betrayal and the setting is a building site in Canary Wharf. One woman appears within a group of construction workers, their foreman and a Jesus-like character. She is a beauty and sexually provocative, driving the men mad with frustration until they gang rape her. She is tossed from man to man, disappearing beneath them until she is left battered in mind and body. The foreman wants her and he is the only man not to have had her, which enrages him. With a beautiful and brutal twist of her head, he breaks her neck. He is the character of Judas. When Jesus comes forward to guard her body, the foreman kisses him, which is a signal to the other men to kill him. They stuff his body inside a wreck of a car. Mortified by what he has done, the foreman hangs himself from a girder. The steel beam is symbolic of the Judas Tree, with its pink flowers, that Judas Iscariot is said to have hanged himself from after betraying Christ.
The Judas Tree turns the heroic romanticism of classical ballet on its head. When first performed, in 1992, it was controversial and divisive. Squeamish critics described it as misogynistic and voyeuristic. Others applauded MacMillan's ability to create provocative and challenging ballet. MacMillan was moving classical ballet on, they argued, encouraging audiences away from the repressed emotions of traditional ballet.
When writing The Judas Tree, MacMillan had the Russian dancer Irek Mukhamedov in mind. Mukhamedov is Bolshoi trained, dark and muscular, with a powerful masculine presence. He was the Bolshoi's leading male for nine years. MacMillan found the Russian dancer inspiring and the role of the Foreman in The Judas Tree was written for him. They created the character together, giving him complexity as the sexually frustrated man who is vindictive in lust and the remorseful murderer, a man who knows not what he does.
Sadly, MacMillan died soon after creating The Judas Tree. Mukhamedov performed the ballet in 1992 and now he is at the Royal Opera House again. He's 50 years old (he looks younger) and this time he is not dancing but teaching the role of the Foreman to a younger, equally powerful, dancer – the Cuban Carlos Acosta, who is a star and the Royal Ballet's principle guest artist.
Sitting side by side on a sofa, there are parallels between the two men. They are dark, handsome and elegantly macho. Neither displays a hint of diva although there is a spark, a sense of mischief, beneath their faultless manners. Acosta, now 36, is mature for a dancer and both men agree that one has to be a man to dance the role of the Foreman, for it could not be played by a boy.
"Carlos will bring a natural maleness to the role and that's what it needs. It has to be a person whom the other boys will respect. The Foreman is a physical presence. And Carlos doesn't need to play the foreman to be that. He is the male, the bull, with his presence.
"Carlos is unequalled in the ballet world. He has presence on stage, which means that everybody is watching him. The same thing happens to me. It's magnetism and that's what it's about.
"One of the points of The Judas Tree is that there is no arguing with the Foreman. He is about respect. When everyone is ignoring him and pushing him away, this leads him to murder," says Mukhamedov.
The moment of the girl's murder is terrifying but her rape is perhaps more disturbing. The build up is tense. We, the audience, know something awful is about to happen as she teases the men, flicking her legs high and sashaying up close. It is a provocative scene and it has been controversial. Mukhamedov explains: "This is how I understand men. Most of the time if they had a chance, they would think about it. It's how the situation happens. She's making the situation come to that.
"It should be disgusting to watch. No one should be pleased with this situation. It's tough but it's fantastic. It's exhausting to watch. Without the rape scene something would be missing."
The raped and murdered woman is played by Leanne Benjamin. Like the men, she is out of the ordinary. She is a principal dancer with the Royal Ballet and at 45, she is one of their oldest. She was with the Royal Ballet under Sir Kenneth MacMillan and danced The Judas Tree with Mukhamedov, back in 1993. She is tiny, strong and muscular, a perfect match for Acosta. He, though exhausted after rehearsals, is full of enthusiasm for the role and the darkness it involves. "There are not a lot of roles like this. It's a big challenge and it's great. It's very boring to always play the prince. Romantic roles become one dimensional with no room for depth. It becomes just about steps. But this role is beyond. The energy is different."
For Mukhamedov, the power of the dance is in the mystical strength of MacMillan's choreography. He says: "With Kenneth's choreography, it's not the steps, it's something else. The steps come out of the psychological thoughts. The psychology of it is powerful. Kenneth loved to go deeper and find the darker side of character.
"It's very difficult to come back from. After performing Judas, I could be difficult with my wife. I couldn't just start smiling straight away. It gets you down. It's emotionally demanding. It can be frightening, breaking a neck every night."
For both men, a dancer is far more than his steps. The great dancers are beyond technique, and their talent has many elements to it: as an actor, a personality and an artist.
The demands of dancing the role of the foreman is suited to them both. Acosta trained in Cuba and Mukhamedov in Moscow and they believe that the tough discipline of their training helped to make them both great dancers.
"The number of famous Cuban and Russian dancers must mean that it's in the discipline. It is discipline that makes talent grow. No discipline and talent will be lost," says Mukhamedov.
"The Cuban school was very influenced by the Russian school," says Acosta. "We both dance big. The stages are enormous and if you are not able to dance big then you will get lost."
They are both now international stars, living far away from home. Acosta is based in London and Mukhamedov in Athens. Mukhamedov has no nostalgia for home. He left his home in Kazan and moved to Moscow when he was ten years old and has been on the move ever since, living in England for 15 years. Acosta is nostalgic about Cuba and the sadness of leaving home. "I am entertaining the world and my family are not part of that. I am doing The Judas Tree and it's all wonderful and my family won't be there to see it. It has been like this for a long time. Dancing is home for me. In life you need to make decisions and it can be unpleasant – but you do it for the sake of your art. You always put your art first, even if sometimes it leads you away. It's not a decision that's easy to make. I am very much Cuban."
Who knows what his family would make of The Judas Tree. Over the years, it has thrilled and outraged. The beauty of the dancing is not in doubt – and that is where the discomfort lies. To be seduced by brutality is not easy and for the puritanical, it must be hard to see violent sex and death made so gorgeous.
"Kenneth was always avant garde," says Mukhamedov, "he has always been misunderstood. And it was the same at the particular moment when this ballet was introduced. Nearly every one of his ballets was not accepted straight away."
"That's what was great about him," says Acosta. "Everything he does is so meaty. It has depth and brings up lots of questions. I love that about him. His ballet has meaning. That's why I came here, for Macmillan. His work is not romantic; it's beyond that. It's contemporary. It's closer to our world."
'The Judas Tree', Royal Opera House, London WC2 (020 7304 4000; Roh.org.uk) 23 March to 15 April