The start date has been announced for the fourth season of Line of Duty.

The new six-part story stars Thandie Newton (Westworld) as AC12’s “most devious opponent yet”, alongside returning regulars Martin Compston, Vicky McClure and Adrian Dunbar.

Newcomers to Season 4’s cast also includes Jason Watkins (Being Human), Lee Ingleby (The A Word) and Royce Pierreson (Our Girl).

The opening episode will air at 9pm on Sunday 26 March on BBC One and finds DCI Roz Huntley (Thandie Newton) and her team in the thick of a career-defining case, Operation Trapdoor.

Pre-order Season 4 on DVD on Amazon here.

Watch the new trailer…

Line of Duty launched on BBC Two in June 2012.

Buy the complete Season 1-3 box set on Amazon here.

Are you looking forward to Season 4? Let us know below…