Bertie Carvel on Dalgliesh and both acting and directing

"Once again the series offers three very distinct stories, each with its own flavour – the locations are a big part of that. Northern Ireland has so much to offer filmmakers, within a short radius,” says Carvel, 47.

"In Cover Her Face, Dalgliesh is called upon to peer into the cauldron of social, political and ethnic prejudices that mark a poignant and uncomfortable resonance between 1979 and our present moment.

"In the country home of an influential British Indian family, the housemaid, a young working-class single mother, is found dead – but Dalgliesh uncovers a web of resentments that reach right across the class divide.

“Devices And Desires takes Dalgliesh to a nuclear power station on a remote headland, where a serial killer appears to be on the loose. He is reunited with Kate Miskin, who is running the local investigation and, discovering she has moved on, must ask himself if he is ready to do the same.”

Carvel, who is known for roles in Jonathan Strange & Mr Norrell, Doctor Foster, and The Crown, also sits in the director’s chair for the second two-part story of the series, Cover Her Face.

"I like a challenge. Both roles require laser focus, so to perform them at the same time was intense, to say the least. But they are also complementary. One of the most important parts of the job is establishing a symbiosis between actor and director, and that rather comes for free when they are one and the same person.”

Carvel is joined by a guest cast including Adam James (Mr Bates vs The Post Office), Josie Walker (Belfast) and Richard Lintern (Silent Witness)

“One of the great pleasures of this show is the rich seam of British acting talent it mines. It makes my job very easy, both as an actor and as a director. I could not have wished for a more extraordinary company of actors for Cover Her Face. Their talent, focus and goodwill made every day a joy.

“It’s a rule of thumb in the genre that when a really fantastic actor turns up they are usually the killer. Dalgliesh upends that trend by cramming every cast with fantastic actors, each of whom, by that rationale, would be a safe bet for the murderer. So we keep people guessing. The scripts are the key to that. Helen Edmundson reimagines the original stories with the careful attention to psychological detail that first-rate actors delight in. It means we punch well above our weight.”

The latest episode of Dalgliesh is on Channel 5 at 9pm tonight.