There are some unwatchably violent scenes in this powerful if flawed police corruption thriller. A miasma of despair and evil seeps into every corner of the world that director Gerard Johnson conjures up, like carbon monoxide. DI Michael Logan (Peter Ferdinando) is a Met drug squad officer who has secretly invested £100,000 in a cocaine route being opened by a Turkish gang. When this connection is brutally taken over by a couple of murderous Albanian brothers, Michael has to open a discreet channel of communication with them if he is to get his money back – something he explains away to his menacing superior officer DI David Knight (Stephen Graham) as cultivating intelligence sources. It is an ambiguous practice that has made corruption a way of life for him, and which is to lead to carnage.

This movie has a hint of Donald Cammell and Nic Roeg’s Performance in the west London locations, and Nicolas Winding Refn’s Pusher trilogy: there are some great scenes simply showing Michael hanging out with his fantastically dodgy crew: Martin (Neil Maskell), Chris (Gordon Brown) and Keith (Tony Pitts). There is great black-comic energy in that group relationship and it is a shame that the plot trajectory takes Martin away from them.

The movie moves on to some grandstanding moments, before finally painting itself into a corner. The ending is frustrating: it runs out of ideas before the final credits. But Johnson packs an almighty punch.