There's a new must-watch crime drama coming to Channel 4: the poignant Baghdad Central, set during the Iraq war. Stars Waleed Zuaiter and Bertie Carvel tell Georgia Humphreys what to expect from their characters.

It's October 2003. Saddam Hussein's regime has fallen. For 6 months, Baghdad has been occupied by American forces.

Muhsin al-Khafaji, an Iraqi ex-policeman who has lost his job, his house and his wife, is living amidst the chaos, desperately trying to keep his sick daughter Mrouj safe.

That's the backdrop for Channel 4's new, 6-part thriller, Baghdad Central, written by Stephen Butchard (it was inspired by Elliot Colla's debut novel of the same name).

Waleed Zuaiter is brilliant as Khafaji. But when he first auditioned, he wasn't sure if he wanted the role.

"I had not long lost my father so I was really down, but my agent had been tracking it for a couple of years and said, 'It feels like it's written for you'," confides the California-born actor and producer, 49, known for films like Omar and London Has Fallen, and TV series Altered Carbon and The Spy.

"I didn't want to play another accented Arab on Western television, but my wife read with me and encouraged me. When I did the self-tape audition and spoke the words, I had a feeling this project and character were special.

"The writing is so rich and deep and character-driven, and a quarter of it feels like a foreign-language film. There's a beauty in that and it elevated everyone's performances."

In the first episode of this nail-biting, emotive dual-language drama, Khafaji ends up being recruited by ex-police officer Frank Temple, a Brit whose aim is to rebuild the Iraqi Police Force from the ground up.

"His initial reaction to Temple is: this guy wants me to work for him to make him look good," explains Zuaiter.

"Then the idea of helping out his sick daughter is introduced, so there's an opportunity for him to get care for his daughter in the Green Zone. Mrouj's kidneys are failing, but because of his low state of mind, she has more or less become his carer.

"And then he can also use his access to gather information about Sawsan (Leem Lubany), his other daughter who has disappeared and with whom there is a certain tension. So - he sells out and becomes a collaborator."

When he discovers Sawsan's disappearance is linked to the murder of an American employee, he entwines himself in that investigation to uncover the truth about what has happened to his daughter and her friends.

The complexity of his character was something that really resonated with Zuaiter; there's "this whole choice of loyalty to country or loyalty to family".

"He's torn, he's conflicted. And at the start, he's at the lowest point of his life, and I resonated with that."

"His sense of pain and everything has knocked him down, and when you're in that situation - I've been there - where your kids look up to you for strength and you don't have it, that hit me right off the bat."

Being a show about war also made it a very personal project for Zuaiter, who largely grew up in Kuwait.

"My family has struggled in war and poverty, we have lived from pay cheque to pay cheque, been evicted unjustly and experienced Saddam's invasion of Kuwait in 1990.

"I was born in Sacramento, lived in Kuwait from the ages of five to 19, went back to the US for college but returned to Kuwait for my brother's engagement party - then Saddam invaded. Because they'd closed the border to Saudi Arabia, we - me, my parents and my 93-year-old grandmother - had to get to Jordan.

"It took us three days, but we made it. It was when my adulthood started, a loss of innocence."

Carvel, 42, has, of course, had very different experiences growing up; he was born in Marylebone, London, and won a place at RADA after studying at the University of Sussex.

What struck him about Butchard's writing was how much space there was, "which is space that is filled by an audience's imagination, an actor's imagination".

"It's a gift, really. It's space for genuine character and depth, and you can sit in the character."

The Olivier-award winning star is famous for stage roles such as Miss Trunchbull in Matilda the Musical and Rupert Murdoch in Ink, while he's best known on telly for BBC One drama Doctor Foster.

How exciting was it to work with such a diverse cast on Baghdad Central?

"Incredibly so," he enthuses. "We are used to seeing stories set against the backdrop of conflict in the Middle East, but which centre on a British or American hero. Protagonism is privilege, so it feels important that this story is told from the perspective of an Iraqi family and told by such an incredible cast from all over the world.

"It was exciting, when we all met at the read-through, to hear so many different perspectives on the region and its politics: Jordanians, Iraqis, Palestinians, Brits - each of us with our own stories and angles."

He did lots of reading in preparation for the role, including Rory Stewart's memoir; a young British diplomat, in September 2003 he was appointed as deputy governor of a province in the southern marshland region, by the Coalition Provisional Authority (a transitional government of Iraq).

What also jumped out for him was information about Iraq's ancient history, as he says it re-framed assumptions he had about where Iraq sits in our consciousness in a "positive" and "bittersweet" way.

"My favourite line in the whole series actually is Khafaji's neighbour turns to him as he's looking out on the desolate city and says, 'Civilisation was born here'.

"It just goes to the heart of the thing, I think, and speaks somehow to Khafaji's poetic soul, and this incredible, beautiful city."

He notes: "With the world on fire around him, Khafaji finds solace in poetry. I find that deeply moving - it speaks to the resilience of the human spirit in terrible adversity. But it's wry as well. There's something about the juxtaposition of nobility and barbarism that speaks volumes."

Zuaiter reflects further on how the series resonates with him watching the series back, "especially living in the States and being involved in all these wars that we are".

"It's like, 'When are we going to evolve as humanity?'" he suggests.

"I think it says a lot about evolution; are we meant to be self-destructive?"

He adds earnestly: "It's not OK to just survive. At some point, we have to thrive, not just survive.

"We have to do something that's bigger than our own self-interests and, to me, that's what's inspiring about the show."

Baghdad Central, Channel 4, Monday, 10pm.