As a brutal winter descends, they work to create a community and to keep faith alive when all humanity appeared to be lost.

“We were there for2½ to three months, and the weather got progressively worse and worse,” Craig recalls of the filming.

“We did the occasional night shoot and while we didn’t sleep out there in the forests, it was hard.

“We ate a lot and drank a lot of vodka; it seemed the only way to get through it. It was certainly the nicest way to get through it.

“After a week being in the freezing cold, stamping your feet, you kind of got into it. The forest was amazing. It’s a real wilderness, and once you get in there you can imagine what it was like.”

He says he was fascinated by the brothers’ true story, particularly the situation thrust upon his character, Tuvia, who doesn’t want to be a leader and is forced into a fight for survival.

“One of the things I liked about this part is that Tuvia doesn’t want to save the world. He just wants to survive and live, and I think we all feel like that.

“Then there’s that really fascinating moral switch which happens in his head – he can’t just save his family, if he’s there, he’ll have to save other people, too.

“The vast majority of stories we hear about heroes are embellished afterwards, because they’re good for morale. They’re good for all of us. Usually, though, the truth is much more complicated and much more interesting.

“My grandfathers fought in the Second World War and saw a lot of what went on,” he continues.

“It’s impossible not to feel some personal involvement and that’s why stories like this are relevant. It’s recent history and it doesn’t stop happening in the world.