Endeavour's Shaun Evans was “repelled” by Until I Kill You serial killer

He went on: "But then I thought there’s actually something quite funny in that, interesting territory and you want to be professionally challenged. It’s a delicate balance, isn’t it?

"Because both of these are real people and one doesn’t want to come in with a heavy judgement at the beginning because what are you doing? So I tried to stay away from reading the book and likewise meeting Delia [Balmer]. I watched the documentary and I listened a lot to his voice and looked at his drawings – I had them in my room before we went to set everyday.

"Beyond that, you trying to – like any job – find out the scenes using your imagination and characterisation. Ultimately I’m an actor so you have to come in and just do your work. It was an interesting one, it was unusual in many respects but gratifying in some respects too.”

Evans is known for his roles as Endeavour Morse in Endeavour, as well as Vigil, and is set to star in Betrayal. But in Until I Kill You, he takes on the much darker role of John Sweeney.

The series flips the true crime genre on its head slightly by not pandering to Sweeney's story and instead, focusing on the impact of the events as they relate to Delia and her fight for justice.

Read more:

• Until I Kill You star chose not to meet real Delia Balmer to research role
• Line of Duty and Endeavour stars lead tense trailer for Until I Kill You

Speaking to ITV in a press pack released fro the series, Evans also said that, in relation to it being an "unusual TV programme for ITV to make": "I think so, perhaps. Like I said earlier, I think what’s unusual about it and what drew me to it is that we are focusing on the victim and telling her story but not glorifying anybody else except the victim.

"You’re getting into the weeds of what that was like after the event and that’s what I think is interesting and that’s what is agonising and painful about it. I think that’s unusual for any broadcaster. If you look at the sort of things that have been made recently within the same genre, they are focusing more on the perpetrator and not the victim."

The synopsis for the series reads: "Shattered by the trauma and injuries inflicted by Sweeney, Delia bravely seeks to rebuild her life. But Sweeney returns seven years later and is arrested for the murder of another girlfriend in North London.

"Delia's fragile recovery is shattered all over again as she has to face Sweeney in open court, her testimony vital to the prosecution case against him.

"This is the story of one woman's astonishing will to survive through physical and emotional torment, despite the failings of the institutions which were meant to protect her."

Until I Kill You will air on ITV1 and ITVX from Sunday 3rd November to Wednesday 6th November at 9pm on ITV1.

Check out more of our Drama coverage or visit our TV Guide and Streaming Guide to find out what's on. For more from the biggest stars in TV, listen to The Radio Times Podcast.