Alcoholic Los Angeles cop Tom Ludlow (Keanu Reeves) goes to the line and well beyond it to rescue two kidnapped young girls at the start of this hard-edged and bloody thriller. “We’re the police,” he says, “we can do whatever the hell we want.”

Which is exactly what happens when, while being investigated for alleged wrongdoing by cynical Captain James Biggs (Hugh Laurie, doing an enjoyably grumpy riff on his moody medico in television’s House), he seeks revenge and sets out to clear himself.

Just about every brutal genre staple is here — gory gunplay, a high body count, unlovely well-used LA locations and a long list of familiar characters (an avenging policeman, duplicitous superiors, violent criminals). It is topped off by a knowingly sceptical screenplay (co-written by James LA Confidential Ellroy) and driven hard and fast enough by director David Ayer to keep you watching even when the action is unconvincing.

Reeves, who appears finally to have grown up, is suitably morose and murderous as Ludlow, Naomie Harris overcomes heavy-handed dialogue to make a good impression as the widow of Ludlow’s former partner, and, having won his Oscar playing Idi Amin in The Last King of Scotland, Forest Whitaker goes well over the top as Ludlow’s venal commanding officer.