May I Kill U? You've seen a vigilante cop often enough - but one on a bike? Kevin Bishop plays the put-upon London bobby who gets hit upside his head, morphs into a psychopathic killer and finds notoriety on Twitter (where else?). Writer-director Stuart Urban has come a long way from his TV glory days (Our Friends in the North), most of it in a downwards direction. This aims for giddy black comedy, but the tone is all wrong, the writing is slack and Bishop hasn't enough charm to carry it.