Viggo Mortenson, 51, allowed his experience of fatherhood to inform his upcoming role in an on-screen tale adapted from Cormac McCarthy’s The Road.

Mortenson, who has played some risky characters, said that he naturally filled the role of the father trying to protect his son: “I think he [the father] has an idea of what he wants to do vaguely – he wants to get to the coast, he wants to stay alive, and keep the boy alive.

“In fact, I think it’s caring for the boy that on the one hand that keeps him alive longer than he would have lived otherwise, but on the other hand, it’s what causes him to make certain mistakes, not trust other people, be unkind, really cruel in a way out of wanting to protect the boy.

“He justifies that, and I think in a way what I could see, especially watching it a second time, was [that] I compared it to not just what individuals do when we’re up against it and can be pretty aggressive and defensive, but what societies do sometimes, or gangs or neighbourhoods or countries.”

The father in the intense character study of the same title as the book has to account to his son for the territorial aggression he feels, Mortenson said.