Acting tours de force are rare in motion pictures. The medium doesn’t easily accommodate virtuosic performances in the way that theatre does. A charismatic actor may be able to dominate the stage and an auditorium. This couldn’t happen in a movie, of course.

But Tom Hardy delivers a triumph of extended close-in performing in Steven Knight’s Locke. It’s not traditional, outside bravura acting, but in its subdued, subtly modulated way, it’s a real, if unlikely, achievement. Hardy’s performance isn’t just the foundation and chief element of Knight’s movie, it’s the raison d’être. There are scarcely two minutes when he’s off-camera. Locke almost amounts to a trick, but it’s a remarkably well-handled one.

Hardy’s Ivan Locke is a Welsh construction company supervisor who, on the night before the first concrete pour in the immense excavation for a 55-story building, gets in his BMW SUV and drives away. For the next 84 minutes, it’s just Ivan, his mobile phone and dashboard display and us. There are, to be sure, the recurring voices of several people coming over the phone, all, for one reason or another, trying to get him to change course. Within this restrictive space, and conceit, more happens than you might think possible.

As he travels along an English superhighway (Hardy was actually driving much of the time), Locke has to tell his callers, and those he calls, that “something has come up.” He tells his boss, who calls to fire him, and his wife Cat (Ruth Wilson) that he’s “made my decision” to take care of something unavoidable. He also tells Donal (Andrew Scott), his frightened assistant, that he will talk him through the daunting job in the morning, a process that won’t go smoothly.

The patience and calm that Locke exhibits are harder won than they may at first seem to be, and Hardy’s accomplishment is to convey this. As his life begins to disintegrate in the wake of his decision and departure, Locke is the very exemplar of grace under fire. Hardy and Knight make him a palpable, plausible figure in a literal and figurative tight space. But when Knight relies on the melodramatically dubious device of having Locke speak to the invisible shade of his late reprobate father, that plausibility declines.

Still, the director-writer and star bring this confined exercise off admirably. There’s more human drama in Locke than in any number of more conventional movies.

Opens Friday June 20 at the Amherst Theater.

Watch the trailer for Locke