ITV has commissioned factual drama Appropriate Adult, based on the untold story of how murderers Fred and Rosemary West were brought to justice.

The drama focuses on the period of time between Fred West’s arrest and his suicide on New Year’s Day in 1995, as well as how he confided in Janet Leach who took the role of the ‘appropriate adult’ during his police interviews.

Appropriate adults are appointed to sit in on police interviews with children or vulnerable adults to safeguard their interests.

The Wire’s Dominic West will play Fred West, Monica Dolan will play Rose West and Gosford Park’s Emily Watson will take on the role of Janet Leach.

The two-part 90-minute episodes comes from the award-winning production team behind a series of notorious murder case dramas, including See No Evil: The Moors Murders, This Is Personal: The Hunt for the Yorkshire Ripper and The Murder of Stephen Lawrence.

Executive Producer of Appropriate Adult Jeff Pope said: “Our intention is to produce a sober and thought-provoking drama based on a true story.

“We have developed the script over the past three years and it provides a unique insight into the police investigation which led to the conviction of Fred and Rose West and the crucial role Janet Leach played as the ‘appropriate adult'”.

Julian Jarrold, who previously worked on Becoming Jane, Brideshead Revisited and Red Riding, will direct the drama.