Torture, threats and abuse are part of daily life when you're a slave. If any other director had taken on 12 Years A Slave, those harrowing details might have been played down, but in the hands of Steve McQueen, they're played out in all their goriness.
Just as with his previous films – such as 2008's Hunger, about the Irish hunger strikes, and 2011's Shame, which tackled sex addiction – the Bafta-winning film-maker pulls no punches with his unflinching big-screen adaptation of Solomon Northup's memoir, which tells the story of a free black man who is kidnapped and sold into slavery in 1841, where he remained for 12 years.
The film, co-produced by Brad Pitt, follows Northup after he loses his liberty and is passed from one plantation to another, before he is finally saved.
Some of the most painful scenes were shot in single continuous takes, such as the whipping scene – in which Northup is forced to whip his friend, fellow slave Patsey (a superb movie debut by newcomer Lupita Nyong'o), by domineering plantation owner Edwin Epps (Michael Fassbender) – and another which sees Northup being beaten and then hanged by a noose.
Chiwetel Ejiofor, a London-born actor with Nigerian parentage, and a familiar face for fans of BBC Two's recent series Dancing On The Edge, about a black jazz band carving their way in Thirties London, was McQueen's first choice to play Northup.
He had no reservations about the graphic nature of the film. "As an actor, you just have to slip down the rabbit hole and see what happens," says the 36-year-old. "There was no other way of telling the story.
"It's not like I wasn't aware of Steve and his films, so I knew he would go to all those places and that's what I wanted – to tell the story.
"It's a strange handicap if you can't talk about violence in a film about slavery. You're not going to do justice to Solomon Northup and what he went through.
"It's like doing a film about World War Two and you can't shoot anybody. I don't want to get involved with something that I wouldn't be proud of, or that isn't right."
Ejiofor admits that shooting these scenes was challenging and the mood on set was often solemn.
"Days like that were hard and uncomfortable," he says, "but they were also a real way of connecting with Solomon."
His performance has created quite a stir on the awards circuit – he's already up for Golden Globe and Screen Actors Guild gongs, and the talk of the town is that an Oscar nomination will follow when the shortlist is announced on January 16.
"It's really terrific, really exciting – the reception has been amazing," says Ejiofor, who received a Golden Globe nomination for his portrayal of Louis Lester in Dancing On The Edge.
In the film category, he's up against his fellow Londoner Idris Elba (who portrayed Nelson Mandela in Mandela: Long Walk To Freedom), but he doesn't mind.
"I'm thrilled for Idris as well," he insists. "We've been friends for a long time now – it's been 20 years – so it's exciting."
Part of the appeal of 12 Years A Slave was the opportunity to work with McQueen. "I've wanted to work with Steve since I saw Hunger, which I thought was completely brilliant," says Ejiofor.
"I got the opportunity after that to see him in Amsterdam, where he lives. We had coffee and talked about life and films.
"I wanted to find a way to work together at some point," he admits.
But when the chance came up (Ejiofor says being chosen by McQueen for the role was "a lovely compliment") the actor initially had concerns.
"When I first read the script and then the book, I found it devastating," he says. "I knew it was going to be physically, emotionally and psychologically difficult, and I told Steve I needed to think about it. I found the idea of playing him [Solomon] daunting. I definitely felt the weight of that responsibility. The story with its implications and the wider historical context is a deep responsibility. I had a lot of self-doubt.
"But the impact the story had on me was unshakeable," he adds. "If I was honest with myself, I knew that there was no way that I wasn't going to be involved with it."
Ejiofor, no stranger to the subject of slavery having previously starred in Steven Spielberg's Amistad, says his knowledge about the subject has expanded.
"I thought I knew quite a lot about slavery, or at least the major highlights," he says. "The incredible thing about having a first-hand narrative is the specifics on the different plantations and the different experiences.
"You tend to think of slavery as one homogeneous thing but actually, there's a massive difference between cutting timber, picking cotton and cutting sugarcane, and the different plantations have a completely different internal life."
Ejiofor now says it was a "dream" role, and a "phenomenon" of a cast to work with (Benedict Cumberbatch and Paul Dano also make up the star-studded cast, alongside Pitt as Canadian carpenter Samuel Bass, who helped Northup find his freedom).
He also admits, however, that he needed time to "decompress" when filming wrapped.
"It took me a little while to get out of the mindset," he says. "I took two months to decompress in Brooklyn, where I don't know that many people. But I did live there when I was in my mid-twenties, so I know enough people that if I need to go out and have contact, I can."
Next up for Ejiofor – who is working on a big screen adaptation of A Season In The Congo, which he recently appeared in at London's Young Vic theatre – is a role in JJ Abrams' Star Wars: Episode VII, according to rumours.
He's not giving anything away though.
"Who knows? We'll just have to see," he teases.
"I'm a huge fan of that world and JJ, but I don't know, I can't tell you."
12 Years a Slave opens in cinemas nationwide on Friday