Robert Redford seems undeterred. After a gap of seven years since The Legend Of Bagger Vance he has returned to directing with Lions For Lambs, a drama set during a single day that attempts to find out how the US has ended up in the mess it's in today. The camera see-saws between two seemingly unrelated arguments . . . an attempt by an ambitious senator (Tom Cruise) to persuade a Washington investigative journalist (Meryl Streep) to run a story about a new war strategy, and a college tutorial in which an idealistic professor (Robert Redford) tries to talk a star pupil out of political apathy. At the same time, a potentially damaging situation in Afghanistan is monitored with live infra-red military intelligence footage of Taliban forces closing in on two wounded GIs, whose helicopter has been shot down.

"It's all symbolic, of course, " says Redford. "One teacher or one student is not going to change anything, but the debate going on between them matters.

It's you better wake up, you better do something, there's no excuse for staying silent."

Redford shot Lions For Lambs in California on a small budget earlier this year, rushing it out almost like breaking news. "The project only came to me last September, " he says. "It was a very smart script but I thought, oh no, talking heads, I don't know whether an audience could sit with that. But then I saw that as a challenge. With so many films out there that just go rat-tat-tattat, could you take a film that was really something substantial and make it dramatic and entertaining? It had to be deeper than the issues, because they'd be just yesterday's news when we got it out. So we tease out what are the factors involved in politics, involved in the media and involved in education that led to this situation we're in now, which is not a happy situation. By posing the questions in a dramatic way my intention was to provoke thought."

Does he really think cinema is again becoming a force for change? "I wish I could say I thought it was, " he says, "but I don't think films really change policy at all. There was once a time when I hoped they did. I was naive. In 1970 I made a lowbudget film The Candidate about how we elect people, suggesting it was by cosmetics, not substance. It was the year the 18-year-old vote came in and the hope was that college students who were in uproar about Vietnam would maybe accept it as a vehicle for change. It didn't change anything. Look what we got. Dan Quayle.

"Similarly with All The President's Men. Look how important journalists then were in getting to the truth. And look where we are now. Three Days Of The Condor was about what happens when there's a certain part of the government that's out of control and making life and death decisions for itself. These are all points you try to make in films, hoping they might have some impact. If you make it dramatic, then you feel you've made some commitment as an artist citizen. Has it changed anything? No. But that hasn't stopped me wanting to do it."

He grins. "When I made Butch Cassidy And The Sundance Kid, people said don't wear the moustache. I showed them a picture of the real Butch Cassidy.

Look, he's got a moustache. No, they said, it will ruin your career.

What career, I haven't started yet? It doesn't matter, you'll never get going. You'll look like an idiot. My agent then called. Paul Newman is not wearing one.

That's because his character didn't have one, I said. So the film comes out. It's a big commercial success. Suddenly moustaches are fashionable. And that's the only thing I've ever seen cinema change."

A lean figure in blue jeans and a check shirt, with the gangling walk of a man who has spent a lot of his life in the saddle, 71-yearold Redford, his rugged allAmerican looks weathered by age and the Napa Valley sun, is one of the last surviving genuine stars, along with Clint Eastwood and Paul Newman, who helped make movies what they are.

Although he won an Oscar in 1980 with his directorial debut Ordinary People, and also a lifetime achievement Oscar, astonishingly he's never won for best actor, although he came close with Out of Africa. He grew up during World War Two, the only son of a Scots-Irish milkman who moved in the early 1950s to the San Fernando Valley to set up as an accountant. "I had family who died in Belgium and Okinawa and places like that, " he says. "I've lived through bad times in America, McCarthyism, Watergate, Iran/Contra and now this. If you look at each of those, as I can, you see the same extreme conservative, mean, narrow-minded mindset.

Whenever those people got power, you had dangerous times."

Redford, who won a baseball scholarship to Colorado University but dropped out and went to Paris to become a painter, can empathise with the student played by newcomer Andrew Garfield who claims not to care. "He describes Washington in a way that you have to say, well, he's got a point, " says Redford. "My education didn't begin until I went to Europe at 18. I had to engage with students my age who were very politically informed, and I didn't know anything. I couldn't care less about politics. It was a boring subject with boring people. They would challenge me and I didn't have any answers.

They made me feel foolish and shallow.

"When I got back I tried to share what I'd learned with kids my own age. They weren't interested. They asked, how are the girls? I think that really began my interest in looking at America politically and culturally with a critical eye. And then when I became an actor and was able to produce my own movies I decided I would like to put into film how I was seeing things about my own country."

Although he made his screen debut in War Hunt in 1962 and then starred with Nathalie Wood in Inside Daisy Clover and This Property Is Condemned, he headed back to Europe in 1966 with his 7wife Lola and their two small children. They'd married when he was 21 and lost their first child to crib death. "I wasn't sure I wanted to continue being an actor. I thought maybe I should go back to being an artist. We lived in a tiny village in Spain for five months, and then six months in Greece."

He returned to play a fugitive on the run in Arthur Penn's The Chase and then teamed up with Jane Fonda in a screen repeat of his earlier Broadway success in Neil Simon's Barefoot In The Park, a role he'd originally accepted only by default. "Some people call it perverse, " he says. "For me it's been a question of personal preferences or a kind of personal integrity. There are things I just don't want to do. I don't think they are who I am. Money is a very dangerous part of the equation. You're in a real Faustian dilemma, as I was just after War Hunt. Just at the moment when I had small children and I was barely making enough money to get by on, I was suddenly offered a big TV series.

I didn't want to do something that had me committing to being the same thing over and over again. I was a developing actor. I wanted to play different roles. I was 24. The more I said no the more they kept upping the offer.

So I walked for hours on Santa Monica Beach, I was so confused.

I didn't come to any conclusion. I went to sleep. I woke up. My agent called to say they'd offered an extra $2,000 a week. Okay, I said, now it's easy. The answer is no. Instead I accepted $130 a week to do Barefoot In The Park.

So you make these choices. You go on instinct."

It was instinct again that prompted him in 1980 to launch the Sundance Institute and Festival in the snowy heights of Utah as an improbable launching pad for independent film-making talent. It kick-started the careers of Alexander Payne, Paul Thomas Anderson, Spike Jonze, Sofia Coppola and more recently John Carney, whose Once won the audience award there earlier this year. Redford's wife was from Utah and when they moved there a next-door neighbour who owned farmland called to say hello. "You're not going to see me for very long, " he said. "I'm getting bought out by a big corporation." "Mmmm, " said Redford. "Okay, I'll buy them out and you can keep your land." So Sundance was born out of a good deed and the need to cover his outlay.

As a director Redford has always sought young talent. "I like finding new people. I started Brad Pitt in A River Runs Through It and 11-year-old Scarlett Johannsen in The Horse Whisperer. It makes the movie fresh because people don't say that's so-and-so."

He'll follow up Lions For Lambs with Against All Enemies, an adaptation of US counterterrorism advisor Richard Clarke's best-selling memoir, including his futile struggle to convince the Bush administration about the threat posed by al-Qaeda. As a producer he consistently champions controversial movies such as Walter Salles's portrait of Che Guevara The Motorcycle Diaries.

Inevitably he's come under attack. Politicians and the media seem outraged at the idea of filmmakers dealing with political issues. Why does Redford keep taking them on?

"Gosh, " he says, "this happened to me before, particularly with All The President's Men, " he says. "But it always comes from the same group of people. They shout about 'leftie propaganda'. They accuse you of the very thing they're guilty of and get away with it. The Bush administration had control of the two houses of Congress and the Supreme Court. They had a propaganda machine that exploited the fear factor so that they could get away with almost anything. After 9/11 when my country was in shock and hurt, they asked us to give up some of our freedoms because they had a job to do. We did so in good faith, only to find out we were lied to. More and more people now see the transparency of what actually happened."

He sighs. "So is it riskier for me to make these films?" he asks.

"Yes, it is. And it hasn't always gone well for me. But I'd rather have that."