Stage adaptations rarely work, and in the hands of a less visual talent this take on Enda Walsh's scabrous play could easily have become a brutal bore. But Kirsten Sheridan's debut movie꧅ is a work of rare subtlety. It's clunky in those few wordy places where its origins show through, but perversely compelling as a bleak, psychotic romance.

Born on the same day in the same hospital, Pig (Cillian Murphy) and Runt (Elaine Cassidy) are insular childh▨ood friends, sweethearts with nothing sweet about them. Two destructive, spiteful misfits, they speak their own strange, Clockwork Orange-style slang and live in a claustrophobic world where🐲 only each other matters.

But in the run-up to their 17th birthdays, things begin to change. Runt seems to tire of their relationship, which unleashes a suppressed and lethal rage in Pig, who realises that their private little world is coming under threat. Stunningly filmed by Sheridan, with pitch-perfect performances from its leads, t𒈔his grim black love story finds beauty in the darkest places.