Éanna Hardwicke, the Irish star of the BBC's new true story thriller The Sixth Commandment, has said he was "shocked" when he first read the script, adding that "truth really can be stranger than fiction".
The four-part series, which begins on BBC One on Monday 17 July, "explores the deaths of Peter Farquhar and Ann Moore-Martin in the village of Maids Moreton, Buckinghamshire, and the extraordinary events that unfolded over the following years".
It "tells the story of how the meeting of an inspirational teacher, Peter Farquhar (Timothy Spall), and a charismatic student, Ben Field (Éanna Hardwicke), set the stage for one of the most complex and confounding criminal cases in recent memory".
"It also focuses on how suspicions around Field's relationship with Ann Moore-Martin (Anne Reid), Peter's deeply religious neighbour, unlocked a series of chilling revelations," said the BBC.
"The Sixth Commandment explores the way in which both Peter and Ann were manipulated by Field, capturing the extreme gaslighting, the gripping police investigation and the high-profile trial, while poignantly highlighting the devastating effect of isolation and loneliness as Field closed in on them. It also celebrates both Peter and Ann's lives as cherished mentors, much-loved relatives and adored friends."
"Actually playing Ben felt a bit like going into a labyrinth," said Cork actor Hardwicke, whose credits include Normal People and Lakelands, in an interview with the BBC.
"I had to set aside any horror and disgust I might have felt about what my character had done and get into his headspace. Thankfully, there was loads to read and watch to try and understand him.
"I've always wanted to be able to play people with a distinctly different world view from my own - the thrill of acting is being able to momentarily step into something very different and surrender yourself to that. When it's a character who has done such terrible things, there's a real balancing act in telling that story."
Written by Sarah Phelps (A Very British Scandal, The Pale Horse) and directed by Saul Dibb (The Salisbury Poisonings, NW), The Sixth Commandment "has been made in full cooperation with members of Peter Farquhar and Ann Moore-Martin's families".
"It's a rigorous, authentic portrayal of what happened. But it also shows you Peter and Ann before their lives were turned upside down and taken from them," Hardwicke continued.
"It's really important that their deaths don't define their lives. Sarah has an amazing way of capturing the essence of people.
"We get to see and celebrate Peter and Ann as people before Ben enters their life. I love that broad overview. The second half is very much about celebrating the rigorous police investigation and the court case."
Hardwicke concluded that The Sixth Commandment is "a story that cries out to be told".
"It could be seen as a cautionary tale about people who might live by themselves but who are shrewd, sociable, part of a community - and yet this person was able to manipulate them and ruin their lives," he explained.
"Thankfully, it's an isolated and extreme example, but there is something to be gleaned from that because elderly people living on their own can feel like unseen members of society and minor versions of what Ben did happen to people every day.
"This is a drama that tells their stories with great honesty and authenticity."
The Sixth Commandment begins on BBC One on Monday 17 July at 9:00pm.
