Bold and brilliant, he's the quintessential British auteur. Nick Setchfield talks to Nicolas Roeg.

"Nothing is what it seems in life," asserts Nicolas Roeg, the tea boy who ripened into a visionary. And as he talks of time, space and the knots of reality, he pours tea into hospitality
suite china. "We're making a lot of it up ourselves. We're inventing what we think is the truth. And that's very science fiction, isn't it?"

One of the smartest, boldest British film directors, Roeg has a charismatic intelligence. His films bully and unravel reality as much as his conversations. A septugenerian in combats, he mixes moments of pure otherness with sudden, scalding conviction. He will ruminate on computers, clocks and the internet and then warn that we are all in danger, every second of our lives. Life. Death. Existence. More tea? His eyes may not hold the answers to the universe but you sense that they certainly know how to ask the right questions.

"The freedom of science fiction is fantastic," marvels Roeg, unwrapping a packet of Gitanes as, outside, Leicester Square tries to nail down the notions of time and place beneath a blue sky. "I think it's the most exciting of all the genres. It's an opportunity to take outrageous steps with your values, or expose human values, human frailties. It's a magical imaginary world. It goes back to the Greeks, to pre-history. I think we try and discipline ourselves to think that we are not living in a science fiction environment, but we are, the whole time. It must be rooted somewhere in our souls because there's no imagination without experience."

While Roeg shies from being toe-tagged as a genre director - "That would be very limiting," he argues, "rather like living in a village and never going anywhere else. And the world is so full of knowledge…" - his finest films have seen cinematic fantasy blur into big screen art. A studio tea boy at 19, he moved from cups to clapperboard and finally the lens, handling the second unit on Lawrence of Arabia and finding his eye as director of photography on Truffaut's Fahrenheit 451. Performance (which he co-directed with Donald Cammell), Don't Look Now and The Man Who Fell to Earth saw him bring his own unique, unsettling and uncompromising vision to the screen. By 1985, Big Audio Dynamite were paying tribute with the single E=MC2, a breakbeat hymn to "the sort of celluloid/money makers would avoid".

"Big Audio Dynamite!" laughs Roeg, as smoke curls from his Gitane. "I thought that was a great name for a band! I never know what the money makers are thinking. Everyone has an opinion. That's the one certainty about film - everyone has an opinion, and after the first shot everyone thinks that they can make the film better, and after the last shot they know they can make the film better."

Roeg is in London to promote a video release of his mazy 1973 chiller Don't Look Now, a true mind-scrambler of a movie adapted from a novella by Daphne Du Maurier. Intricate and haunting, it toys with perception and perspective, losing Donald Sutherland in an oppressive Venice of ghosts and fractured time. "I liked the story," remembers Roeg. "It was very spare and it had a very strong plot. The story contained a  certain inevitability that we are not in charge, that all knowledge and all things are connected and they must run their thread out in some way.

"It had a situation in which people were in danger, as we all are, permanently. We're living in great danger all the time. That's part of life. And God knows that now that I'm in my 70s it's all 'you must be careful of this and careful of that', or 'don't do this or don't do that'. Well, it's not going to make much difference anyway. We're only hanging by a thread, and we're here to live. We think we can control life, but we can't control anything. We're constantly taken by surprise. And in the best science fiction or fantasy you can never really second guess it because it does away with all the expectancy of behaviour."

Roeg demurs when asked what he brought to Du Maurier's original words. "That's not the sort of question I can answer," he insists, politely. "If I have a particular vision, it can only come out of the work. Other people can tell me what it is, but  I wouldn't know. You never know yourself, do you? Take Goya. He only had one eye. Now you may look at his figures and say that they are extraordinary, but he would never be able to tell that. And if he had both eyes then they wouldn't be extraordinary at all."