Everest: Jason Clarke takes on Rob Hall

How hard has it been filming Everest?

We went to Nepal and up in the Alps but wasn't as tough as I'd thought it would be. I honestly thought it'd be a lot more difficult, physically. It's actually been quite enjoyable filming in Italy, London and Nepal. That offsets most of the hard stuff. Yeah, we had some days up there that were pretty cold but that actually made the acting easier: when you walk on set and it is a mountain, you're pretty stuffed because you're at, like, 5500 metres, in Nepal. There's not really a whole lot of acting required at that point.

What did you discover about Rob Hall, playing this role?

I did a lot of research and I met Jan and Sarah in New Zealand, a long time ago. I think what I discovered about him was the man's patience and his love for what he did. I also had a couple of diaries from the time, which I read through, and they were a great help.

Just reading through that he was thinking about building at Namche to try to sustain it long-term, and that he foresaw the problems that were coming-up, like waste disposal, cheap buildings, everyone flocking to it [Everest] and thinking that, long-term, as a group they had to be responsible.

Rob had a reputation for being very fastidious about cleaning up rubbish, taking out everything that you'd left behind. From the people I talked to - the Sherpas, the Nepalese that were still there and the guys who ran the Garuda Hotel - they look on him very fondly. He was a guy who genuinely cared about the area and, I guess, his long-term business, for which Everest was one of the main mountains. It was the beginning of what we now know is huge numbers now going there. His group then was small compared to what we have now.

Actor Jason Clarke stars in the movie Everest.

You climbed in New Zealand?

Yep, we went there. I'd done some climbing, previous to this film, then we went to Ben Nevis actually when there was a big storm up in Scotland, so we were up there on Ben Nevis during a massive storm. Then we went to New Zealand and climbed a couple of peaks that Rob did back in the day with Guy Cotter, who worked with us on this film and was a very close friend of Rob's. Marty Henderson and I did as much training as we could, just to get into the New Zealandness of it. We just wanted to have that experience - like cops, soldiers or people you work with - of going through something together. Marty and I did a couple of serious peaks, where it got a bit hairy, with some good guides.

How hairy did it get?

We went up the top of a peak in the Tasman glacier, and it put us to the test. You go up there and there's just 10 points of crampons holding you between the ice and 11,000ft straight down. There were 60km winds and the guides were shouting: "Stand up, Jason! Stand up!" And I just wanted to sit down, because it [the drop] was straight down!

But things like that give you an understanding of what these guys did for a living.

Did meeting Rob's widow and daughter place extra responsibility on you playing this guy?

Yeah, of course it does. That's always a consideration. I don't know if it's a slippery slope, but it's definitely an edge you need to be aware of, particularly as Sarah's only 17. I like to get to know people and if I think they're okay and they understand what we're doing and I'm transparent and the production is transparent then you can learn a lot. I want to do due respect to his legacy as a father and the man he is to New Zealand.

But also there's that line of where you've got to be responsible to the story and to what happened; the real events and the mistakes that were made. They've been great about it, they've been very good about it and just talking to Jan and going through stuff, like songs they used to sing to each other, things that they talked about and she took me through the phone calls and you just get into the pace of their lives and the way they lived. I hiked with Jan, a bit - we went walking - and it was just nice to have that connection. I also think - even aside from doing the job - that it's one of the great things about being an actor: you get to meet people who let you in, and do things that you wouldn't ordinarily get to do.