David Threlfall and John Simm are set to play the pioneering team who introduced DNA fingerprinting to police investigations, a landmark discovery in tackling crime.

Shameless star David has been cast as Detective Chief Superintendent David Baker in ITV drama Code Of A Killer, while Life On Mars actor John will play Dr Alec Jeffreys, who first invented the technique that was the biggest leap made in criminal investigations.

The drama follows DCS Baker as he investigates the brutal murders of Leicestershire schoolgirls Lynda Mann and Dawn Ashworth between 1983 and 1987, and how Dr Jeffreys’ DNA fingerprinting, which he developed at Leicester University in 1984, changed the course of events.

A teenage boy had confessed to one of the murders, but when evidence from the crime scenes was analysed for fingerprints, Baker and Jeffreys made the shocking discovery that his confession was false, and the world’s first DNA manhunt was launched.

Executive producer Simon Heath said: “Code Of A Killer is a testament to the pioneering science of Alec Jeffreys and the foresight and determination of David Baker. Together they brought justice for two grieving families and changed the course of criminal investigation forever.”

Lorcan Cranitch, Robert Glenister, Siobhan Redmond, Anna Madeley, Dorothy Atkinson, Andrew Tiernan, Jaz Deol, Hannah Walters, Lydia Rose Bewley and Ged Simons also star in the drama, which is due to begin filming this week in Leicester and London.

Both Professor Sir Alec Jeffreys and Detective Chief Superintendent David Baker have been consulted about the programme, as have the families of both victims.