From the moment that the young man inserted a tiny camera on an endoscope down his throat, so that the audience could see his vocal cords as he spoke, it seemed that this was going to be a disturbingly different version of Julius Caesar. Onlookers were not disappointed: the actor playing Mark Antony had throat cancer and was reduced to croaking out his immortal lines because of a laryngotomy; Caesar himself was an old man displaying his physical fragility through a haze of white pubic hair; the Roman assembly was evoked with a live horse and a walking chair; and Brutus and Cassius were transformed at the end into two snarling anorexic women prowling a wasted landscape. If you were trying to sum up the contradictory sensations it provoked, you might say that it was not unlike one of Bosch's images of hell, filmed by Tarkovsky. A rumbling soundtrack, like a looming storm or a volcano about to erupt, added to the sense of apocalyptic unease.
Audience members either love or hate Romeo Castellucci's unique theatrical vision. No moderate reaction is possible: he is there either to be hailed as a theatrical visionary or to be denounced as a tailor not merely of the Emperor's New Clothes but of an entire new regal fashion-chain. Visually startling and conceptually radical, when he brought Giulio Cesare to London two years ago, he was accused by many critics of producing a physically repellent and irrelevant take on Shakespeare's original text. Even as one of the critics who favoured him, it was with great surprise and increased respect that, after turning back to the original text, I realised that not one of his seemingly outlandish images was unfaithful to Shakespeare's disturbing metaphor.
An invitation to Prato, therefore, to see Castellucci's latest work, Genesi which comes to the London International Festival of Theatre (LIFT) next month seemed a welcome chance to re-explore the bewildering and fascinating terrain of his vision, as well as to meet the director himself. Perhaps because I was expecting someone huge and intimidating, to match his work, it was a surprise over that weekend to discover a young man with tight curly brown hair, an attractive, unassuming smile and a constant band of disciples composed of his many children and members of his company.
In the warehouse where his play was being performed, he explained that he did not start out in theatre, but studied the plastic arts, and declared that he wanted "to break through the constraints of text and focus on the more direct medium of the image".
Genesi, as its title implies, is based on the first book of the Bible. But Castellucci sees within the story of any beginning the terrors of the possible destruction that will follow. So instead of starting with Adam and Eve, he takes the audience to arguably the most politically and scientifically significant starting-point of the 20th century: the discovery of radioactivity.
At the house of Marie Curie, bars of radium glow with their thrilling yet sinister energy. A small group of people stands in a garden, looking reverentially towards the metal. A tall man who we discover is Lucifer steps forward and starts to sing an unearthly Hebrew lament. Castellucci, who works mainly with non-actors, has chosen an anorexic to play Lucifer, and as he sings, his thin, elongated fingers dance a ghostly dance over the discovery that killed its inventor. Then he strips off his clothes and leaves this civilised social scene by squeezing with agonising difficulty through two parallel poles.
It is a thoroughly modern re-enactment of Lucifer's banishment into chaos and darkness. The second he succeeds in his task, the soundtrack screeches into feedback, as the audience watches this naked man screaming and flailing with despair. Scott Gibbons's score is another way of ensuring that Castellucci's audiences do not experience emotional detachment for a second. The director tells how: "We think about the musical structure of the performance from the very first moment. The lights, the actors, the machines every single element is planned according to the music."
This is an indication of how, although Castellucci's work is tightly intelligent, he does not allow his audiences initially to react with their minds, but forces them into purely emotional territory. Strongly influenced by Artaud's theatre of cruelty, his production uses rhythm, movement and unearthly sound to go beyond the mental architecture we have constructed to interpret most of the events we experience.
Interval chit-chat over white wine and peanuts can inevitably only skim the surface of what he has achieved. Critics trying to describe his productions find themselves groping for words that initially sound vapid and pretentious a phenomenon not entirely helped by his own somewhat opaque programme notes. And yet every single aspect of Castellucci's work is thoroughly rationalised. He reveals that he is never without a notebook, and each production takes several years to plan.
Genesi is divided into three acts. After the Mme Curie episode has cast its light on the price humans pay for eating from the Tree of Knowledge, Castellucci goes back to Adam and Eve for the first act, visits Auschwitz for the hypnotically white tranquillity of the second and finishes with the story of Cain and Abel. Castellucci writes that, as the murderer of his brother, Cain is the most important mortal for the writer of tragedies. As the figure who destroys what he loves, he also exemplifies the apocalyptic interpretation of the human condition permeating these startling images.
Castellucci has been often accused of creating freak shows, because he frequently uses human beings who are physically deformed or different. When we first see Adam, for instance, he looks like a random pile of flesh lying in a glass case; it is only when he starts moving that we realise he is a skilfully arranged contortionist. The naked Eve has a mastectomy, Lucifer is anorexic, and Cain has a withered arm. The impression you get, however, is not of a strange Victorian-style spectacle, but of an interest in and, although it may sound odd, love of the human condition in all its forms. In this intriguing visual world, it also gives them a strange undefinable power to reach beyond the limits of the socially lauded body beautiful.
I ask Castellucci how strongly he is influenced by Stanley Kubrick, because of his obsession with the rhythm, dramatic power and, sometimes, comic potential of machines. Two stuffed, mechanised sheep copulate in a glass case at the back of the stage; a detached, mechanical writer's arm scrabbles helplessly on the floor; a human figure revolves at top speed on an electric turntable. He tells me that Kubrick's 2001: A Space Odyssey was a strong influence on the way in which he structured the largely dialogue-free Genesi. As with the late film director, the precision of the mechanical detail is intense: technicians come into the theatre three hours beforehand to set up the whole production.
Whether people come away with an image of a metallic robot clapping its hands or a live dog one of the only random elements pissing against a backdrop, Castellucci takes the audience to an area where only prolonged thought can deal with each individual's disorientation. Perhaps it is precisely because of the confusion he arouses that he represents an important force for maintaining the excitement factor in theatre today. The result is viscerally and turbulently unforgettable. The theatre of indifference is dead.
LIFT begins on Monday (020-7863 8017); 'Genesi' is on 5, 6 and 7 July, Sadler's WellsReuse content