Is Until I Kill You a true story? Inside the real-life horror of Delia Balmer and serial killer John Sweeney

The ITV series, Until I Kill You, is set to premiere on November 3. The four-part series will be accompanied by a companion documentary titled Until I Kill You: The Real Story.

Anna Maxwell Martin takes on the role of Delia Balmer, while Shaun Evans portrays John Sweeney.

The real Delia Balmer penned a book about her harrowing experience living with a serial axe murderer, titled Living With a Serial Killer. The series draws its narrative from this book.

The chilling true story unfolds in 1991 when Delia was employed as an agency nurse in London. At the age of 40, she lived alone and led a solitary existence.

She encountered a man at a pub who introduced himself as John Sweeney, four years her junior. Their initial meeting didn't lead anywhere, but they crossed paths again weeks later on the street, reports the Mirror.

Sweeney asked Delia out, and although she initially declined, his persistent advances led her to write him a letter - a decision she would deeply regret.

Sweeney, a casual labourer living in a squat, was eager to move into Delia's home.

Delia remembered his explosive fits of rage and wanted him gone, but fear held her back from asking him to leave.

After enduring two years of an abusive relationship, she finally mustered the courage to ask him to leave in December 1993.

However, he continued to manipulate and control her, with things escalating in the spring of 1994 when he held her hostage in her own home for several days.

He bound her to the bed and threatened her with a gun and knife, warning that he would cut out her tongue if she screamed.

During this horrifying ordeal, he confessed to murdering his ex-girlfriend, Melissa Halstead, revealing that he had dismembered her body and disposed of it in an Amsterdam canal.

After seven days of captivity, Sweeney finally released Delia, allowing her to return to work.

But the terror didn't end there. In July 1994, Delia sought help from a women's refuge and informed the police.

Despite this, the authorities did not take significant action on the initial reports, leading to two further attacks on Delia that year.

Even after changing her home's locks, Sweeney broke in and subjected her to more abuse, holding her captive for another day.

When she failed to show up for an appointment with a friend, the concerned friend contacted the police who discovered a bag at Delia's home containing tarpaulin, masking tape, surgical gloves, and rope - Sweeney's murder kit.

A week later, he was released on bail under the condition that he returned to his parents' home in Skelmersdale.

However, he violated his bail conditions and went back to Delia's home, where he carried out an almost fatal attack.

On December 22, 1994, as Delia was returning home from work on her bike, she saw Sweeney approaching her outside.

He attacked her with an axe, striking her arms before stabbing her in the breast and thigh with a knife.

A neighbour, alerted by the noise, intervened, hitting Sweeney with a baseball bat which caused him to flee. Delia was then rushed to hospital.

Despite her injuries, she miraculously survived, but was left with significant physical and emotional trauma.

Sweeney managed to evade capture for six years before his location was discovered.

Under the alias 'Joe', he returned to London where he met Paula Fields, whom he murdered in December 2000.

The Metropolitan Police launched a murder investigation and identified Paula's body through DNA analysis. When Sweeney was apprehended, he was found to be carrying a gun and a knife.

Police confiscated over 300 pieces of his artwork, many of which depicted his horrific crimes.

Ultimately, it was this artwork that provided the crucial evidence police needed to link him to multiple murders, leading to his life sentence.

Until I Kill You airs on ITV from November 3