"They forget that I did a play, or don't know that I did a play [] with Daniel Craig, or that I spent a year doing a musical playing Peter Allen, who was very gay and flamboyant, or , or Gaston in ," he says.

But if his Oscar-nominated performance as Jean Valjean in last year, didn't change these cinema-goers' ideas about the 45-year-old actor's versatility, then his portrayal of Keller Dover in Prisoners will. Dover is a religious survivalist who takes the law violently into his own hands when his daughter is abducted.

Wolverine is an unalloyed superhero, but Dover is darker, more ambiguous, and disturbing. He is the embodiment of America's anxieties about its response to the events of September 11, 2001: a man who goes after monsters and discovers the monstrous in himself. Emotionally, this made him the most difficult character Jackman has played on screen, and that was part of the draw.

"One of the things that intrigued me, and frightened me, was the sustained intensity and emotion of being in hell from page eight onwards," the actor says. "That is difficult and challenging, and that's a turn on. It's also frightening, because you're not sure you'll pull it off. But that's the risk you've got to take."

Filming the movie in sequence meant that by the time he got to a harrowing scene where Dover threatens someone with a hammer, a moment of madness that will stun many of his fans, Jackman was practically running on empty.

"I remember thinking, 'I'm out of energy. My gas tank is done. I'm over emotionally, physically, every way,'" he says. The actor thought he had nailed the scene on the second take, but instead of congratulating him, director Denis Villeneuve firmly told him: "Hugh, I need you to go there."

When the cameras rolled, in a fit of anger and frustration, Jackman slammed the hammer into a wall, just a hair's breadth away from cast member Paul Dano. "I had no idea I was going to do that," he says, "and it shocked the hell out of me. There was still 2 per cent of my brain that was aware, so I wasn't going to put it through his head. But I got there because Denis pushed me."

The moment of spontaneity was frightening. But Jackman says it was also a breakthrough, and he thinks it could change the way he works in the future. "Although I'm well prepared and do research, sometimes my head can get in the way," he says candidly. "I really noticed that Jake [Gyllenhaal, his co-star] has a great ability to just be instinctive on camera, even though he also prepares a lot." The take brought out a similar quality in Jackman: "I was able to just let things go."

Quebec, Canada-based Villeneuve, who is making his English-language directorial debut, agrees. "It was very, very impressive what I got out of [Jackman] when he was angry. I still have shivers when I think about it. I love the fact that he was ready to go into that ugly part of himself and did it without judgment."

The lengths Dover goes to try and find his daughter turn him into a torturer. The film portrays this unflinchingly, and what it has to say about the nature of violence, was part of what appealed to Jackman.

"I've done seven movies playing Wolverine where the violence is weirdly celebrated. People go to see the violence; they clap and cheer it," he says. "But real violence is uncomfortable. Real violence is messy and the collateral damage is huge, and I think it's important to look at it."

The shoot took him to some dark places, but Jackman says it was nothing compared to the research he undertook. The actor researched real-life child abduction cases, and found himself confronted with tales of pain and madness that were "way more violent and more horrific than this film".

He was particularly struck by the story of a man whose five-year-old daughter went missing. The father was driven mad by the knowledge that she would be waiting for him, not another rescuer, to come through the door and save her. "Everybody around him was saying, 'Calm down, just let us do our job,' and it drove him crazy. I would tear up just reading all that stuff. As a parent I could really relate to it."

Jackman and his wife, Australian actress-filmmaker Deborra-Lee Furness, protect their children, Oscar and Ava, by keeping them out of the spotlight.

Jackman enjoyed a normal life growing up, and he wants them to have a similar experience. But, the actor jokes, no one wanted to know what his accountant father did, and it takes a bit more planning when the paparazzi are on your back.

"I don't want to walk around with security guards, but there are some situations I won't let them [his kids] be part of, because I know there may be some danger for them. It's something my wife and I talk about. I just try and be as normal as I can, as I don't want them to be paranoid about going out," he says.

Jackman is now embarking on a three-month break, and audiences will see him again next year in . That was a special project for Jackman, because it reunited him with Bryan Singer, the director who gave him his break as Wolverine in the first film in 2000.

There can't be much of Wolverine left for him to explore. So will he finally lay the mutton-chopped man-beast to rest? "Weirdly, I'm enjoying it more than ever," he says. "In , the sixth movie we just did, I was actually able to explore things that I hadn't been able to explore before. So we'll see for the future. It would have to be very compelling."

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opens on October 31