It is impossible to watch this British prison drama without permitting thoughts of Alan Clarke's Scum from swimming aggressively into the brain. Starred Up doesn't have quite the same degree of narrative punch – indeed, it does a lot of meandering – but there's enough grit and sincerity to stand its ground against that vintage drama. That counts as proper praise.

Two things allow Starred Up to stand apart from the pack: a rigorous attention to prison procedure and a stunning breakthrough performance from Jack O'Connell. The midlands man plays Eric, a former young offender coping with his first days in an adult prison (the film's title references that unwanted elevation).

The opening sequences reek of research and integrity. We watch as – nonchalantly immune to the indignity – Eric is strip-searched and led to a cell, where he immediately sets about preparing the space to his needs.

The screenplay, by Jonathan Asser, a former prison counsellor, captures both the ritual of prison life and its characteristic emotional stresses. It helps that much of the film was shot in Belfast's Crumlin Road Prison. No studio-bound set could fake the grimly utilitarian ambience of a genuine place of detention.

None of this would matter much if the performances weren’t up to scratch. But O’Connell is, quite simply, a revelation. Constantly on the point of explosion,he manages to be simultaneously wired to the moon and touchingly vulnerable. It’s little wonder that the Derby-born actor is currently being vigorously courted by Hollywood.

Sadly, Starred Up never locates quite enough narrative thrust. Ben Mendelsohn is powerful as the protagonist's dad, also interred at the prison, and Rupert Friend is believable as a well-meaning counsellor (presumably modelled on the screenwriter). A little less incident and a little more focused story would, however, have been most welcome.

For all that, Starred Up still grabs you by the throat and throttles you into submission. Just check it hasn't thieved your snout on the way out.