Delia Balmer, the only known survivor of serial killer John Sweeney, continues to live with the trauma of her ordeal. In 1994, after ending their three-year relationship, Sweeney held her hostage, tied to a bed for four days, and later attacked her with an axe. Despite her survival, she still sleeps in the same bed she was tied to, according to screenwriter Nick Stevens, who dramatised her story in the new ITV drama Until I Kill You.
Balmer's experience is recounted in her memoir Living With a Serial Killer, which forms the basis of the drama. Stevens noted that Balmer's PTSD made her appear agitated and angry when they first met, but he realised this was a result of her trauma. He also suggested that her combative nature may have contributed to police taking six years to apprehend Sweeney and link him to the murders of two former girlfriends. Sweeney is now serving multiple life sentences.
Anna Maxwell Martin, who plays Balmer in the drama, emphasised the complexity of her character. 'I find Delia a fascinating and complex person,' she said. 'I've never had any interest in the audience sympathising with or liking my character.' The actress chose not to meet Balmer until filming was nearly complete, instead studying tapes of interviews to prepare.
Shaun Evans, who plays Sweeney, noted the challenge of portraying a serial killer without resorting to stereotypes. 'If you present as psychotic or evil at the beginning, it's not very interesting for the actor or the audience,' he said. 'But also, Delia's not daft. If he'd been a terrible threat from the beginning, she would have spotted it.'
The drama aims to explore how the criminal justice system treats victims, especially those who do not conform to expected behaviours. Stevens sent Balmer the scripts and received detailed feedback, including notes on the position of a mug on a table. 'She was always reasonable in the end,' he said.
