When Anna Maxwell Martin announces a new project, we sit up and listen. From Line Of Duty to Motherland, A Spy Among Friends to Hollington Drive, the star has a knack of picking roles that pique our interest.

Her latest venture is Delia Balmer, a brand new true crime series from ITV which is set to tell the extraordinary true story of the woman who survived a near-fatal relationship with the murderer John Sweeney – and whose testimony was eventually crucial in the prosecution case against him.

Maxwell Martin will take the lead role, appearing opposite Endeavour and Vigil star Shaun Evans, who plays Sweeney.

Here’s everything you need to know about the upcoming drama. 

What is ITV’s Delia Balmer series about?

Working as an agency nurse in London, Delia Balmer leads a largely solitary life. When she meets John Sweeney in a local pub in 1991, they immediately strike up a connection.

Sweeney seems free-spirited and artistic, but this persona has a darker side, eventually leading to a series of violent attacks on Delia. During one, he tells her something truly horrifying: that he killed his ex-girlfriend and disposed of her body in a canal in the Netherlands.

He is arrested soon after, but is granted bail when the court fails to recognise just how dangerous he is. Sweeney then attacks Delia again, before disappearing.

Grappling with the trauma of her past relationship, Delia tries to rebuild her life, but Sweeney is eventually arrested for the murder of another girlfriend seven years later. She must then face him in court, as her testimony forms a vital part of the prosecution’s case.

According to the broadcaster, “Delia Balmer narrates the ordeal Delia suffered at the hands of John Sweeney, and her traumatic journey through the police and criminal justice system as they attempt to prosecute him for his crimes.”

Who will star in Delia Balmer?

ITV is yet to confirm the show’s supporting cast, but with Maxwell Martin and Evans in the lead roles, we can surely expect to see some high calibre talent joining the line-up.

Maxwell Martin has described the show as telling “an important story” and shared her hope that it “will do Delia due diligence”, while Evans has referred to the drama as “a story that is quite rightly told through the victim’s lens”.

Who else is involved in the show?

Delia Balmer will be produced by World Productions, the production company behind hits like Line Of Duty, Vigil, Bodyguard and The Pembrokeshire Murders. The scripts have been written by Nick Stevens (who also wrote The Pembrokeshire Murders), based on Balmer’s book Living With A Serial Killer.

ITV’s drama commissioner, Huw Kennair-Jones, described the series as “a testament to the resilience of the human spirit when facing unimaginable evil”.

“Nick Steven’s scripts have brilliantly captured the fortitude of a truly remarkable woman and her journey to achieving justice and the obstacles she had to overcome,” he added.  

When will Delia Balmer be on TV?

As the series has only just been announced, we’ll have to wait a while before we know exactly when it is set to air on ITV1 and ITVX, but we’ll keep you updated as soon as we know more. 

Images: Getty