"In the dark, if there's distance, you are lost," Andreas Heinecke says consolingly outside his "Dialogue in the Dark" exhibition. Originated in Frankfurt, this controversial exposition of sensory deprivation and non-visual perception has been touring Europe since 1989 and this week reaches London's South Bank.
Inviting you to negotiate four everyday environments in total darkness, led by a blind guide, the basic idea of "Dialogue" is very simple, yet the expectations with which people enter and the responses it evokes are infinitely complex. Art event, adventure, social experiment, or worthy consciousness-raising exercise? No two people emerge with the same impression.
A small group of strangers strides down a dimly lit corridor, a curtain parts, and we stumble into utter darkness. No shadows. No shapes. Just darkness, heavy and impenetrable. Instinctively, hands reach out for reassurance, "Who's that? Who's there? Is that you?" Some people are struck silent, others gabble desperately to fill the void. Insecurities start to emerge.
From out of the darkness comes a calming voice which offers soothing directions, leading the group past fragrant herbs and running water to a little bridge. Crossing gravel, turf and paving, we start to discern the world through the soles of our feet. Gradually the sound of birdsong gives way to raucous traffic noise and we feel our way on to a street, into a house, then out into a bar.
Proffering a random fistful of change, Kevin, the RNIB press officer, tries to buy a round from the blind barman and pandemonium breaks out. Drinks pass up and down the counter in an improvised slurp it and see system. "No, that's not mine." "Who wanted the Coke?" "Who cares if you've just dabbled your fingers in it. Over here." If our little tea party is anything to go by, Heinecke was wise to abandon the supermarket area he experimented with in Vienna: people were confused and so curious to find out what was in the packages that the floor became covered with rice and ketchup.
Groping for a table, we finally sit and begin to talk. For the bar is the central arena of the exercise, an opportunity to engage with guides and fellow explorers alike in a levelling environment. Here, the darkness begins to feel liberating. After all the scurrying around among foliage and traffic bollards, just sitting without visual distractions is exquisitely relaxing. We draw closer, concentrating, really concentrating on what people are saying. Not looking at the clock, fiddling with our hair, sizing up each other's appearance or trying to interpret body language. The subtext of "Dialogue" is tolerance - the ultimate blind date, where communication is pared down to its purest form.
A keen caver and pot-holer, Ian Turner, 22, usually works as a massage therapist but he's relishing his time as a guide. "It's quite stressful, but I love it. I have albinism and usually people think because you look different you're some sort of simpleton or freak. In the dark I'm just judged on my personality, my voice and the way I've interacted with them as a guide."
Ian is one of a team of 28 guides, all blind or partially sighted, leading tours that leave every 10 minutes. Coming from all walks of life - physiotherapists, solicitors, civil servants, graphic designers and piano tuners - the guides find "Dialogue" as weird an experience as sighted visitors.
"It's a new experience, walking without my guide dog, and I've never used a stick before either," says Mary Gentry, a small, round woman in her late fifties. She usually has little interaction with the sighted world at the sheltered factory she has worked in for the past 35 years, doing printing and heat-seal welding. "It's a whole new world for me," she says, "but I'm looking forward to the challenge."
Co-ordinating and training the guides is the formidable installation manager, June Bretherton, who is herself blind. Since only 4 per cent of the one million visually impaired people in Britain have no sight at all, isn't she worried that "Dialogue in the Dark" will only serve to reinforce people's fears of blindness as afrightening world of blackness? "Certainly, the exhibition starts off with people's normal perceptions of blindness, but hopefully once they've talked to the guides they'll have much greater awareness of blind people. I also hope they'll have enjoyed themselves and have realised that their imaginations can still run wild when they can't see." The installation may not provide a realistic simulation of blindness, but it's a pretty potent metaphor.
"I'm a catalyst," says Heinecke, who is keen to observe how British people will cope with the exhibition's enforced intimacy.
"I was looking for a bridge to break down silly prejudices," he explains. "It's not an exhibition about blindness. It's about communication. All of this is just a setting, a platform to link people, to bring people together."
"You don't need rarefied language to appreciate this," says the installation's designer, Huw Chadbourn. "It's so accessible."
Chadbourn has built a temporary structure for the installation in the undercroft area beneath the Queen Elizabeth Hall, a dusty concrete cavern long since appropriated by skateboarders. In a now much-reduced space, a handful of them are leaping 15 yards down a flight of steps and over a chair. They are fuming about this new intrusion into their territory, but when I offer to take them round the exhibition they accept.
And so Craig, Sam, James, Richard and Joe amble curiously into the lobby, reluctantly exchanging their boards for white canes. Each of them has skated around the space every day for years, but in the dark they are totally disorientated. "This is insanity, man", "total madness". "I'm scared," whimpers Joe, the youngest. "Don't leave me behind." Every few yards he suggests he has found a skateboarding landmark - "the banks" or "the big driveway" - but he lacksconviction. Suddenly a great whoop of recognition goes up from Craig, a 23-year-old Glaswegian who has been skating the South Bank on and off for 10 years, "Hey, I've crashed into that! Feel this - it's the pebbly wall."
Senses heightened, Sam, 17, emerges into the light: "I can smell the South Bank, man. When I came out it was different. I never noticed it before, but yeah, the smell was just South Bank."
"It's like a game at first," says Richard, 23, a part-time DJ. "Then you get into a real-life situation like a road or a pub and it's really difficult. I had a really good conversation with the barman about cooking. How do you time pasta? How do you know if it's boiling? Things you take for granted. Without this you'd never get to understand it. It just makes you aware and it's quite shocking."
"You know, if I was blind, I'd want to live by the sea," Richard suddenly decides. "It was very aesthetically pleasing, the sound of the water in there. If you were blind, that kind of environment would be beautiful to live in."
It may not be art, but "Dialogue in the Dark" achieves something most artists only dream of - an experience that lives on outside the exhibition.
n 'BT Dialogue in the Dark' continues until 18 June at the Royal Festival Hall, 0171-928 8800. Advance booking is strongly advised