When Delia Balmer first met John Sweeney in a Camden pub in 1991, there was no way of knowing the kind of monster he was. Affable and charming, she was immediately drawn to his creative, free-spirited nature, and they began a romantic relationship.

This magnetism quickly faded: John Sweeney was a psychopathic serial killer.

Anna Maxwell-Martin (Motherland) will star as Delia Balmer, whilst Shaun Evans (Endeavour) takes the mantle of John Sweeney.

Maxwell-Martin said: "Telling an important story with the excellent team from World Productions, producer Ken Horn, director Julia Ford and a brilliant cast is always an exciting proposition! As it is brought to life by Nick Stevens, hopefully we will do Delia due diligence."

The series guides viewers through Delia’s journey meeting, living with, fleeing and finally testifying against the murderous John.

Extensive research has gone into the drama, written by celebrated true crime screenplay writer Nick Stevens (The Pembrokeshire Murders).

“A few months after reading Living with a Serial Killer, I had my first meeting with Delia Balmer. She was unlike anybody I'd ever met before."

"Still suffering from PTSD ten-plus years after John Sweeney’s conviction, Delia is, though she would never admit it, a hero. A survivor whose determination to pursue the good in life – to dance, to travel, to live - is ultimately greater than her demons," Stevens told ITV.

The show will be produced by World Productions, who have brought many gripping TV series to our screens, including Line of Duty, Bodyguard, Vigil, Anne, Save Me, The Pembrokeshire Murders and Karen Pirie.

No release date or title has been announced yet, but the show will premiere on ITV1, as well as streaming on ITVX.