Although debutant writer/director Craig Viveiros’s pressure-cooker prison drama throws in all the usual ingredients – brooding antihero, naive new prisoner, psychotic troublemaker, bent screw, violent internal politics and male rape – there are some meaty performances to chew on. With only three months to serve, model prisoner Jack (John Lynch) is gutted when his wife abandons him on the anniversary of their son’s death. ‘Find someone who really needs saving,’ advises his gnomic pal Ahmed (Art Malik). Enter young, newly arrived arsonist and artist Paul (Martin Compston from ‘The Disappearance of Alice Creed’). Their protective father-son relationship is threatened, though, by jealous, manipulative Clay (Craig Parkinson), who – in collusion with corrupt guard Donner (David Schofield) – rules the wing with quiet threats and sharp objects. Some will find the final revelation a coincidence too far, and a more experienced director would have trimmed 20 minutes from his own wordy script. But given Lynch’s incandescent intensity, Compston’s fragile vulnerability and Craig Parkinson’s slyly insinuating turn as Clay, this is first and foremost an actors’ showcase.