Life and death are confirmed by last-minute telephone calls in Clemency, a quietly devastating drama told through the eyes of a death row inmate bound for the chamber and a long-serving warden, who must remain emotionally detached until the final injection of potassium chloride stops heart function.

Writer-director Chinonye Chukwu wanders the same echoing corridors as Dead Man Walking, The Green Mile and Just Mercy, exploring different facets of the American criminal justice system.

Her second feature is emboldened by a fearless central performance from Alfre Woodard as the sleep-deprived warden, who is as much a prisoner of her hulking facility as hundreds of men in her care.

Over the course of two riveting hours, Woodard chips away at her character’s armour, which she wears to protect against visible twinges of doubt, until trickles of saltwater break through and smear her unmovable, cold facade.

Her omission from this year’s Oscar nominations was also considered by many to be an injustice.

Aldis Hodge also delicately reaches into our chests to rip out our hearts with a measured supporting performance as a prisoner, who has always pleaded his innocence.

It is available for streaming on Curzon Home Cinema.