When is The State on Channel 4, what is the terrorist drama about and who are the cast?

Director of acclaimed TV drama Wolf Hall Peter Kosminsky is back with another TV series set to dominate discussions: the tale of four Brits who travel to Syria to fight for Isil. But when is it on - and why is it must-watch television?

What is The State about?

The State is Channel 4's powerful new drama charting the lives of four British men and women who travel to Syria to join Isil. The key characters are Jalal, 19, whose brother died fighting for the caliphate, Ziyaad, 19, Jalal's friend, Ushna, 18, a student, and Shakira, 26, a doctor and single mother who takes her nine-year old son Isaac.

Upon arriving in Raqqah the men begin combat training while Shakira tries to save lives and Ushnka joins the Isil female moral police. However the group of Muslims quickly become disenchanted by the realities of rape, beheadings and child soldiers and begin to question their choice.

The cautionary tale, written and directed by Wolf Hall's Peter Kosminsky, airs days after Islamic State took credit for an attack in Barcelona and is expected to stir controversy due to its nuanced approach to radicalisation.

Baroness Warsi wrote in The Telegraph earlier this week: "What makes the series difficult viewing is not just the violence – especially against children – but the ordinariness of the young Britons who have chosen to make this environment their home.

"So often we have lazily defined those attracted to violent ideologies promulgated in far-off countries as mad, bad misfits and yet the reality is far more complicated... It takes the viewer on a journey to where the mad and bad become real and human."

When is The State on Channel 4?

The State first aired on Sunday 20 August at 9pm on Channel 4. The four-part series will air at the same time on consecutive nights over the course of the week, finishing on Wednesday 23 August.

• Read: The State episode one review - Peter Kosminsky proves that the devil is in the detail

Who are the cast of The State?

The series stars Havani Seth as student Ushna, Ony Uhiara as doctor Shakira, Nana Agyeman-Bediako as Shakira's son Isaac, Sam Otto as Jalal, whose brother died fighting for the caliphate, and Ryan McKen as Jalal's friend Ziyaad.

How realistic is The State?

The series is founded on an intense research project by the director. Kosminsky was joined by a team of Muslim researchers who scoured social media and had first-hand discussions with people who have made the journey to Syria before shooting began.

Speaking at a screening in London, Kosminsky said: "I do feel that dramatists’ job is to hold a mirror up to society and - given the fact that thousands of Brits decided to go over there and now that some of that issue is spilling back onto our streets in London and Manchester and other European cities and capitals – I just think this is an issue we need to address.

"‘Will this increase Islamophobia?’ is obviously something I’ve had in the front of my mind for the whole process, because that’s the last thing I want to do", he added.

What are people saying about The State?

The daughter of David Haines, who was executed by the group in 2014, said the show should have been postponed following last week's attack in Barcelona. 

Writing in the Daily Mail at the weekend, the 20-year-old said: "The last thing those families need is a drama about Islamic State on TV at the same time their lives have effectively been torn apart by that same group," she said.

Television viewers were divided on Channel 4's decision, taking to Twitter to vent about the drama.