Kelly Macdonald is joining the cast of the sixth season of the BBC’s Line of Duty.

She will play Detective Chief Inspector Joanne Davidson, the senior investigating officer of an unsolved murder, whose unconventional conduct raises suspicions at AC-12.

Macdonald will start work on Line Of Duty series six when filming begins next year, opposite series leads Martin Compston, Vicky McClure and Adrian Dunbar, who are also confirmed to return.

Line of Duty writer and showrunner, Jed Mercurio, said: “DCI Joanne Davidson will prove the most enigmatic adversary AC-12 have ever faced.”