The filmmaker passed on the film about real-life pacifist Desmond Doss twice before realising it was a movie he had to make, and then he set about creating a hell on earth for battle scenes in Okinawa, Japan.

Some early critics have taken issue with the film's violence, but Gibson insists he could not have shot the war scenes any other way.

"I wanted to be realistic in a war situation," he tells WENN. "Okinawa was the greatest loss of life in the South Pacific. I mean the Japanese even described it as a steel rain of bullets. Napalm was used. So I wanted it to be real."

The Braveheart director is proud of his new movie - and the story it tells about the heroism of Doss.

"I think it also highlights what it means for a man with conviction of faith to go in to a situation that is hell on earth; a situation that reduces most men to animals and in the midst of that maelstrom this man is able to hone his spirituality and achieve something higher, above war, above religion, above everything," Mel adds.

"He goes in and he performs acts of love in the midst of hell, which is the beauty of the story and the pinnacle of heroism. Real superheroes don't wear spandex tights! What Desmond shows and what I find the most inspiring thing is he managed to transcend and get above a war we'll always have and always will have."

And Mel hopes the film's message will resonate around the world, reminding mankind of the horrors of war.

"This movie is a vital message now," he says. "The world is in a pretty bad way. It's been this bad before and it's gonna get that bad again. We seem to learn a lesson; stings like a b**ch. We behave for 20 or 30 years and then we're back at it again. It's like history regurgitates itself.

"This is hopefully a little word or a reminder about that and a little look at the brutality and viciousness of it. I want you to feel appalled by it but I want to accentuate the other side of it that in the midst of it some good can be extracted."