Marcella

ITV, 9pm It comes as no surprise to see the troubled detective (Anna Friel, below) losing her grasp on reality. Already in a bad place before going undercover, her efforts to ‘become’ dodgy cop Keira Devlin now push her to the limit. To make matters worse, a series of events prompt Finn to wonder if Keira/Marcella is all she seems. Katherine, meanwhile, ruthlessly disposes of those standing in her way of gaining control of Belfast's underworld.