You don't need to have seen Bill Gallagher's 2004 BBC series Conviction to recognise the small-screen roots of Blood, which begins in a relatively standard Sunday evening telly vein. After a 12-year-old girl is murdered, hardened and emotionally distant copper Joe Fairburn (Paul Bettany) becomes obsessed with tracking down her killer, with the case reminding him of an unsolved one from his past.
The police arrest Jason (an unsettling Ben Crompton), a smug and unrepentant creep with a history of child abuse. Joe and his more sensitive brother Chrissie (Stephen Graham) are convinced of his guilt, but he's released due to lack of evidence. This does not sit well with the increasingly unpredictable Joe, and an impulsive act of vigilante justice sends both brothers spiralling into moral decline.
Despite the limitations of Gallagher's script, director Nick Murphy (The Awakening) steers a crisp, compelling path as the walls begin to close in - Jason's disappearance arouses the suspicions of the brothers' domineering ex-cop father (Brian Cox), now suffering from dementia, and their level-headed loner colleague (Mark Strong). But he allows his actors too much leeway to indulge, and both Bettany and Graham overplay some key emotional beats, marring what are otherwise solid performances.
The film's at its strongest when it leaves the police station behind altogether, diverting into stranger territory in a series of eerie beachside scenes that play more like science-fiction than teatime drama. Murphy and his cinematographer George Richmond transform the Lancashire coast into something like a hostile alien planet, offering no comfort to any of Blood's compromised characters.
But visuals aside, this is still a story better suited for the small screen. You can feel the unfulfilled desire to stretch out, to unfold a family saga with real scope, but in the absence of that space Blood resorts too often to histrionics. It's a brusque and intriguing thriller that plants itself firmly in the moral grey area, but it's let down by clunky scripting and an apparent allergy to subtlety.