In the pursuit of corruption, how far will they go to uncover the truth? The hit police thriller is back with a brand new investigation in this much-anticipated third season of Line of Duty, taking another probing look at modern policing and corruption within the force. When AC-12 are called in to investigate Danny’s conduct, even they could find themselves in the firing line. Daniel Mays (Common, Public Enemies) plays Sergeant Danny Waldron, the highly proficient leader of an Armed Response Unit whose unpredictable behaviour is becoming a threat to colleagues and suspects. When AC-12 are called in to investigate Danny’s conduct, even they could find themselves in the firing line. The third season of Line of Duty is written by Jed Mercurio and produced by World Productions for BBC Two. Mays joins returning cast Martin Compston (Sweet Sixteen) as DS Steve Arnott, Vicky McClure (This is England) as DC Kate Fleming and Adrian Dunbar (Ashes to Ashes) as Superintendent Ted Hastings.