It was only after Ilya Kabakov's departure from Soviet Russia to the West, at the age of 55, that he moved away from painting – a medium which had earned him an eminent reputation in Moscow – and began constructing installations that took up entire rooms and engulfed the viewer on entry. Until this shift, he had worked as a painter and children's book illustrator. It was the same year – 1988 – that he was reunited with Emilia, a childhood family friend who had moved to the West some years earlier, and began a life-changing relationship with her, both romantically and artistically.
Ilya and Emilia Kabakov married in 1992 and are now celebrated as pioneers of a monumental form of installation art. Ever since 1988, they have been creating "total installations". Their works feature in museum collections, including the Museum of Modern Art in New York and Tate Gallery in London. They are the first living artists to have their work bought by the Hermitage museum in Russia, and billionaire international art collectors, Roman Abramovich and Dasha Zhukova among them, buy their pieces for millions of pounds. In 2008, one of Ilya Kabakov's paintings alone sold at auction for $5.8m.
In their most recent installation, The Happiest Man, which can currently be seen at Ambika P3 gallery (the University of Westminster's art space), and is on sale for $1.5m, we enter a room in which a reel of "happy" films are running along a wall. We can view the film from inside a smaller room representing a house, and from here, we become "the happiest man" of the title, looking out at the escapist images of the film from the comfort of his home.
Speaking from their adoptive American homeland in Long Island, Emilia explains the reason for Ilya's shift in art medium. In the early 1980s, still in the Soviet Union, he began to grow dissatisfied with the limits of the canvas, but it was not until he left for the West that another more encompassing and multi-dimensional mode of art became necessary for him.
He turned to installation art because he feared that his new audience in the West would not understand the effects of living under the Soviet regime unless they were placed inside it. The effect of the "total installation" was to manufacture art that was "felt" by his viewer.
"By the time he decided to go to the West, Ilya was full of feelings of hate for Soviet power and the situation in which the government suppresses you. He thought it would not be enough to show in a painting and wanted to explain the atmosphere. He feared that people wouldn't understand what it 'felt' like to live in the Soviet state. It was very important for him to create the atmosphere so that people could be immersed in it," explains Emilia.
"With a total installation, there is no divide between the artist and the audience. In a way, you create a painting and you allow the viewer inside the painting, which has become three-dimensional instead of one-dimensional."
So audiences are typically saturated by the stories that the Kabakovs tell through their monumental works. They become the characters in the art that is taking place all around them. For example, in The Toilet (originally erected for Documenta IX in 1992) viewers stand at the corner of a house in which they hear intermittent singing coming out of a toilet. Niccolo Sprovieri, who has known the Kabakovs for two decades and showcased their work at his gallery in London 14 years ago, reflects on this powerful work: "You are by the toilet in the corner of a room. You hear the voice of someone, sometimes singing, sometimes laughing. The idea is that everyone has shared rooms in this house and there is only one room in which you can be alone, a place where you can express yourself without fear of being judged."
In I Sleep in the Orchard, viewers enter a woman's bedroom, complete with fake plants and a painting of the countryside. A text accompanying the work reveals that this woman moved from the country to the city in hope of improving her fortunes but suffered a mental breakdown and was hospitalised. The picture on her wall is an effort to recreate her countryside childhood idyll.
In Palace of Projects, an Artangel project that was exhibited at the Roundhouse in London, viewers walk in spirals and encounter different imaginary characters. These works typically reflect the Kabakovs' strong desire to tell a story through their art.
Emilia says the audience's response to such works is invariably a powerful one. "When they enter a total installation, they go into a different dimension in a way. The atmosphere takes over and people come out completely astonished. I remember in 1993 a South American who saw The Toilet came out crying. He said 'that's exactly how my grandmother lived'. He had never been to the Soviet Union. The effect is universal, very intimate and personal".
Ilya is now aged 79, and Emilia is 67, yet they continue to work at a furious pace. Their numerous plans for next year include exhibitions at the Pace gallery in New York and the Grand Palais in Paris. Both wake up at 6am and work seven days a week, with one assistant to help them construct sometimes vast pieces.
Michael Mazière, curator of Ambika P3, says the couple are internationally respected as pioneers of large-scale installations. "They are the reference point for large, immersive installations that construct entire worlds. And their work has a more metaphorical point of view than the traditional Western point of view," he says.
The legacy of Soviet Russia is discernible in their work. Even The Happiest Man has a double-edged significance. While the screen of utopian images of happy people in green fields taps into a universal human desire for escapism through film and cinema, the footage the Kabakovs used is Soviet propaganda.
"At the beginning, we wanted to use a film from 1930s Hollywood, which was [essentially] a Cinderella story. But we compared it to a film from 1930s Soviet Union which was about the happiness for all – the people in the film are simple people and they're all happy. It's a true utopia because everyone is happy."
What's more, the footage still carries a contemporary significance in Russia today, adds Emilia. "Some people in Russia have started thinking that Soviet times were utopian. Someone asked some children what they thought of Stalin and they said 'he was a great leader'. [Soviet times] have been transformed into movie fiction. A lot of people think like this – they think that paradise was created and it is now destroyed."
The Happiest Man, Ambika P3, London NW1 (020 7911 5876) to 21 April. Two Mountains, Sprovieri Gallery, London W1 (020 7734 2066) to 11 May