Casting a glance around the dilapidated grandeur of the Langham Hotel bar in London’s West End, John Hurt is instantly recognisable. Surrounded by wisps of smoke, Hurt appears older and more vulnerable than on screen, but as soon as the interview begins, he springs into life.

One of Britain’s finest and most-loved actors, Hurt has never been busier. With two films already on general release, a third, Shooting Dogs, is due out this Friday. After over 40 years of making films, he describes the film - set during the Rwandan genocide - as the hardest he has ever made. A glazed expression comes over his weathered face and his gravely voice softens when talking about the Rwandan project. He was deeply affected by what he learnt and experienced in Africa.

“In retrospect, of course it was the hardest film I have ever made. I was thinking ‘oh, please don’t offer it to me’ because I knew I could never have turned it down. I was dreading it, but once it begins, you don’t let it infiltrate your performance.

“You can only play what is in front of you. You couldn’t allow yourself to think of anything else. However, since filming stopped and life has moved on, it has had a very profound effect on me.”

Shooting Dogs is based on the international failure to react to the genocide of 800,000 people in Rwanda in 1994, despite a mass of evidence both before and during the killings. It will be judged as one of the greatest crimes of the twentieth century, but does not make for easy cinema material. Hurt plays a brave Catholic priest who runs a school in Rwanda along with the other white westerner of the story, a naive and idealistic aid worker having a year in Africa after university. Following the shooting of the Rwandan President, the school becomes a refuge for trapped Tutsis, surrounded by machete-wielding Hutus. The tiny, UN peacekeeping force can only look on impotently, bound by orders to remain neutral. They can only shoot the dogs scavenging on the dead and spreading disease. The irony does not escape Hurt’s disillusioned priest, who asks: “Shouldn’t you wait till they shoot first.”

Filming took place in Rwanda, employing a largely Rwandan cast and crew. Hurt points out that Hotel Rwanda – the other “Rwandan” film - was filmed in South Africa and that Shooting Dogs is a far rawer, real and essentially better film. Despite some artistic licence, the film succeeds in transmitting the horrors of 1994. Nobody in Rwanda was untouched by the genocide and as a result, the filming of Shooting Dogs was a highly emotive experience.

“There were outbreaks of hysteria on set on a daily basis,” Hurt explains. “People we were working with would break down, it was often too much. Every Rwandan had suffered. However, they were incredibly resilient – they had to be. For the westerners there, we had to maintain a sense of humour to get up in the mornings. If you multiply that sense of pain by a thousand, then that was how difficult it was for the Rwandans to come and work every morning.

“I was struck by people’s joy at surviving and the possibility of being able to put it right. To be Rwandan, not to be Hutu, not to be Tutsi.”

The moral question posed by the film is ‘how far would you go’. The whites trapped in the school – Hurt’s priest, the aid worker (Hugh Dancy) and a BBC journalist and cameraman – are given chances to walk away safely. For the hundreds of Tutsi there is no such choice. As the journalist says, the West is not interested; 'they're just more dead Africans'.

“Having the two Europeans was a deliberate dramatic device,” explains Hurt. “The West doesn’t understand their condition, we barely understand our own. However, the point is that essentially we’re all the same in human terms. It would be very easy to be nihilistic about our situation, but one has to believe that we can do the things that human beings are best at – surely without religion – and behave less selfishly.”

It is the third time Hurt has worked with director Michael Caton-Jones, after Scandal and Rob Roy. He is full of admiration for Caton-Jones’s work on Shooting Dogs. It is only unfortunate that much of this weekend’s cinema traffic will head straight to Caton-Jones’s other, very different, release of the week, Basic Instinct 2. It has been an odd week for the director: red carpet premiere with Sharon Stone one night, open-air cinema premiere in Kigali, Rwanda, the other.

Hurt believes it can only be a positive thing that more films are being released that make audiences think about real issues and challenge the idealism that often abounds in contemporary films.

“There are far more films around at the moment that are serious, and by that I don’t mean gloomy. The pendulum has swung in that direction and it can only be a good thing because film has a huge role to play in breaking down barriers.”

Hurt is excellent in the film as the exhausted priest, slowly losing his faith in the wake of the ceaseless atrocities. It is well-known that he shies away from method acting, and insisted that he approached this role as he would any other.

“My father’s a clergyman, so there must be some of that in me, but acting is a leap of imagination. It’s as difficult to defend and describe as a religion. It’s a strange act of faith in a way when you play somebody else. In terms of preparing for the role, the fact that Rwanda happened didn’t make any difference, it could have been fact or fiction. It is only when you come away from the acting it that it hits you.”

Despite Hurt’s reputed dislike of interviews, he seems happy to ramble on with gentle guidance during my two hours with him. It starts snowing outside the window, forcing Hurt to stop his tirade against the “farcical” Baftas, Oscars and the Bush Administration. “I’ve known some very cold winters,” he pauses.

“The thing is, I suppose, we often give ourselves such self-importance. Sometimes, we have to step back and look at the bigger picture.”

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