John Simm on return of detective drama Grace

A household name when it comes to British crime drama, John Simm has become a master of the everyman persona. Transforming flawed, warts-and-all personalities into relatable - and more often than not likable, on-screen characters, the Leeds-born actor's unnerving ability to enthral should never be underestimated.

His latest role as returning Detective Superintendent Roy Grace in hit ITV series Grace is but a prime example. A character haunted by a ghost from his own past in the form of missing wife Sandy - who disappeared seven years previously, Roy's by-the-book attitude to crime solving is described by Simm as "straight down the line". Except, as series one ultimately proved, that wasn't entirely the case.

An adaptation of Peter James' bestselling crime novels - having now sold over 21 million copies of the Roy Grace series worldwide, Grace continues to captivate viewers with a penchant for the macabre. But with Simm, 51, a self-declared bookworm with a notable aversion to television adaptations, what eventually convinced the "squeamish" actor to get involved in such a gruesome project?

"We are working so closely with Peter James to bring the books to life, hopefully fans will continue to be happy with what we've done," says Simm. It's a view shared by the author, who adds that while writing his novels, he had someone who "very much looked like John" already in his mind.

"When ITV said 'what do you think about John Simm?' I said, 'You're kidding?! This is exactly the kind of image I've always had.' He was Roy Grace from the moment I first saw him," says James with enthusiasm.

Simm - best known for his appearance in hit shows including Life on Mars, Doctor Who and Strangers - is now set to reprise the role, with plenty of action and romance on the horizon for his character. Comprised of four feature-length films, the new series is once again brimming with action - an aspect of filming Simm admits he wasn't entirely prepared for.

"Roy's running all over the place," laughs Simm with a shake of the head. "Over the rooftops of Brighton train station - and there's a lot of fighting... Every time I read a novel now I think, 'Oh, no, what's he going to be doing?!'"

A drama which sees the vibrant seaside city of Brighton transformed into a giant game of Cluedo for the detective, the show regularly finds Roy unearthing cold case evidence alongside his colleague, Detective Sergeant Glenn Branson (Richie Campbell).

A character inspired by three days of research on patrol with Brighton Police, the novelist says the 1996 encounter with Glenn - a former bouncer turned police officer - cemented both the character and a subsequent relationship that continues to this day.

"All my novels are drawn to some extent from elements of real life," reflects James, going on to describe a notable encounter some 25 years ago which peaked his interest in crime.

"I was phoned up by a police surgeon in Brighton who said, 'would you come and look at a piece of footage that Sussex Police have seized in a raid with your moviemaking hat on? - from my past life [as a producer]'.

Going on to describe the footage - which appeared to show a girl in her teens being stabbed to death - the novelist was then asked whether he believed the video to be real or a fake.

"I said 'it's a single take; if she's acting, she should get an Oscar'," recounts James, who notes the footage did in fact turn out to be a "snuff movie".

"That was the start of it, that's what fascinated me." adds James, citing it as the source of inspiration for his Roy Grace novel Looking Good Dead.

Adapted by acclaimed screenwriter and Endeavour creator, Russell Lewis, series one saw the detective employ the help of a medium named Harry Frame (Chernobyl's Adrian Rawlins) in a bid to track down his missing wife. But as the lines between personal and professional blurred, the medium's offer of help in relation to an ongoing police investigation ultimately left Roy's public reputation in tatters.

Just as series one focused on the all-consuming nature of crime, conversation quickly turns to the prospect of romance in series two. With Roy continuing to dwell on his wife's disappearance (a subject Simm assures us is addressed head on), forthcoming workplace flirtations with senior anatomical pathology technician Cleo Morey, played by Zoe Tapper, prove a pleasant distraction.

Holding back laughter as he recalls the characters getting "a bit flirty over lots of corpses", Simm describes it as "a good way to start" any romance. With Roy being "quite resistant" to the idea at first, the actor describes how it was "quite sweet" to see his character embrace such foreign emotions.

"We have a lot of other things to look forward to in Grace's journey - with his wife, Sandy, and meeting Cleo and their love match coming together," says Simm. "So there's lots in store besides the wonderful gripping stories of the week from Peter's Books."

Grace airs on ITV from Sunday, April 24.