Slavery is a subject that has been tackled on screen many times before, most recently in Django Unchained, but comparing Tarantino's violent drama to this introspective slow burner is like comparing an ant to a supernova. Steve McQueen's follow up to Hunger and Shame is essential viewing.

Solomon Northup (Ejiofor) is an educated musician living a good life in pre-Civil War New York with his wife and two children. After a drunken sortie with two white men, Solomon wakes to find himself manacled to the floor of a dungeon; pleas of mistaken identity fall on deaf ears and, beaten into submission, Solomon is shipped to Louisiana where he is sold into slavery to first the liberal Ford (Cumberbatch) and then the maniacal Epps (Fasbender)…

John Ridley's (Red Tails) script explores the many faces of racism: there's Paul Giamatti trader driven solely by money; there's the straight-up redneck hate of Paul Dano's foreman, there's Cumberbatch's plantation owner who, despite a tortured conscience, doesn't do enough to help; and there's Fassbender, who thinks he's doing God's will and believes his feelings for slave Patsey (Nyong'o) are genuine.

Released from scripting duties, McQueen still refuses to intrude on the scenes; the one time the camera is noticeable is during an achingly long stationary shot of a slow hanging. The whipping scene in particular difficult - the spray of blood clearly visible each time the lash strikes with McQueen showing the impact a whip has on a bare skin - but the director manages to pull it off without looking like a shock tactic.

It's in this scene that Ejiofor, forced to whip a friend at gunpoint, cements his Oscar credentials. A towering performance that mixes that steely determination to survive and a subtlety in hiding it deep down, Ejiofor is wonderful. There are brave choices in the construction of Solomon: we share his horror when a chance of escape goes begging as a pal leaves him behind, but he does something similar later. He's matched by Fassbender - the unexpected outbursts of compassion undercut the expected Evil White Man depiction but even these sympathetic moments are tinged with his egocentricity. This film's got layers.

But what's really impressive is that McQueen and Ridley consistently surprise with a familiar subject. Some slaves distance themselves from those working the fields, dismissing them with that word; there's the white former overseer who, haunted by his treatment of his underlings, lost himself to alcohol and now must work the fields alongside his former charges; and nearby there’s the friendly plantation owner and his black wife.

12 Years A Slave will linger for a long time after. One of the movies of the year.