Eddie Marsan is set to star in a new TV drama about the real-life murder of Rachel Nickell on Wimbledon Common in 1992.

Eddie Marsan

Eddie Marsan

A crime that shocked the UK, the young mother was repeatedly stabbed in front of her two-year-old son, who was the only witness, as she walked in the park in south west London.

The prime suspect was Colin Stagg, who spent a year in custody, but was eventually formally exonerated by the police and awarded more than £700,000 compensation for his incarceration.

The case went cold for a decade, but, in 2002, the police reopened it and with more advanced forensic techniques officers eventually identified schizophrenic serial rapist Robert Napper as her killer.

In December 2008, Napper pleaded guilty to Nickell's manslaughter on the grounds of diminished responsibility. He was already being detained at Broadmoor High Security Hospital in Berkshire for a double murder that he committed in 1993 but he was sentenced to be detained indefinitely by the judge that oversaw his conviction for Rachel's murder.

The bungled initial investigation will be the main focus of the four-part Channel 4 series.

According to the Daily Mail newspaper's Baz Bamigboye column, 'Ray Donovan' star Marsan, 52, is currently in talks to portray Stagg in the project, which has been written by Emilia di Girolamo and is being directed by Niall MacCormick.

Harry Treadaway - who plays Victor Frankenstein in 'Penny Dreadful' - has already been cast as Detective Inspector Keith Pedder, who was at the helm of the undercover 'honey-trap' operation which involved an officer, calling herself Lizzie James, setting up a pen-pal scheme to try and trap Stagg into confessing to the killing.

In the two books that he wrote after leaving the force, Pedder claimed that Scotland Yard set him up to be a scapegoat for the bungled investigation.

In August, 'The Virtues' actress Niamh Algar was announced to be portraying the policewoman ordered to become 'Lizzie' who makes contact with Stagg.

Announcing the drama and Niamh's casting, Channel 4's Head of Drama Caroline Hollick previously said: "The unique female perspective of Emilia's extraordinary scripts will shine a light on one of the most shocking stories in modern policing, in a drama which combines Story Films' trademark journalistic rigor with sensitivity and nuance.

"And it's a privilege to be working with Niamh Algar, who is fast becoming an iconic star of the channel."

Shooting on 'My Name Is Lizzie' - which takes it's name from the pen-pal sting - is yet to begin.