Although there are a few nice-ish cameos - Ioan Gruffudd pops up, as do James Fox and Jodie Whittaker - it's not enough to save this film from itself or give it any kind of emotional authenticity.

Director Nick Moran obviously feels strongly about the material but fails to create a consistent tone.

Nick Moran -- like Casey Affleck, an actor-turned-director -- marshals his relentlessly grim material unflinchingly, and Rupert Friend, as the adult Kevin, is engaging and convincing in a complex role.

It's so unsubtle in its characterisation and so plodding in its narrative that it's unlikely to reach much of an audience.