Des star Daniel Mays says he was haunted by nightmares of serial killer Dennis Nilsen

From Digital Spy

Des star Daniel Mays has opened up about the psychological toll of working on the ITV true-crime series.

The Line of Duty actor investigates real-life killer Dennis Nilsen (David Tennant) in ITV's three-part drama, which has set new ratings for the year across its transmission this week.

Mays's portrayal of Nilsen's interrogator, Detective Chief Inspector Peter Jay, has earned huge praise from viewers, but playing the role haunted the actor away from set.

"When you're preparing for a role like this, you have to delve into what happened and it was really, really tough," he explained to NME. "I woke my wife up screaming because I was having a nightmare that I was in an attic with Dennis Nilsen."

Photo credit: ITV
Photo credit: ITV

He continued: "The content was really toying with my mind, but that was a great thing to experience because when you look at it and policing at that time and what Peter and his team went through, they weren't privy to any form of counselling or anything like that.

"Their counselling was going down the pub and drinking copious amounts of alcohol, not opening up to their wives. Talking about your feelings wasn't common for men of the 1980s, so the drama is also an amazing investigation into what it was like to police at that time too."

Another unsettling aspect of filming Des for Mays was David Tennant's ability to "uncannily" channel the killer on and off camera.

Photo credit: ITV
Photo credit: ITV

"Sitting across from David during an initial interrogation scene when he looked so uncannily like Dennis was just eerie. I found it as close to what they must have been experiencing at the time and that felt pretty tricky," he remembered.

"David completely embodies the role. He very much kept himself distant from all the actors because of the difficult subject matter – you could tell that he was really in character and he wanted his space. It's an amazing performance."

Des aired on ITV, and is now available to stream on the ITV Hub.

Watch: Camp Confessions with David Tennant

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