Sally Challen was subjected to a false narrative by a criminal justice system that painted her as “a controlling and jealous lover who planned to kill her husband”, her son has said.

In doing so it failed to recognise the decades of abuse and coercive control she had suffered at his hands, David Challen writes in an article for today’s Observer that is heavily critical of how abused women continue to be viewed by the courts, a concern that women’s rights campaigners said they shared.

Sally Challen, 65, was 56 when she bludgeoned 61-year-old Richard Challen to death with a hammer in 2010. She was jailed for life for murder, but the conviction was quashed and a new trial ordered for next month.

However, the Crown accepted her plea to the lesser charge of manslaughter on the grounds of diminished responsibility, meaning she had served her time in prison.

While hailing the verdict as a “watershed”, David writes: “How has our mother’s case come to be so inaccurately portrayed by the criminal justice system? Why do we continue to label women who kill as jealous, cold murderers and refuse to explore evidence of abuse?”

He explains that his mother was only 15 when she met their father, who was 21. “At first he was charming, but gradually the abuse began,” David writes.

“He bullied and humiliated her, isolated her from her friends and family, controlled who she could socialise with, controlled her money, restricted her movement and created a culture of fear and dependency.

“Our father fed into our mother’s mind the abuse she was suffering over 40 years was normal.”

But this behaviour was not examined during the original trial, meaning, David writes, that for “almost a decade my brother James and I have been forced to accept a false narrative of our father’s death that depicted our mother as a controlling and jealous lover who planned to kill our father”.

Legal experts described the verdict as significant. Rebecca Christie, who specialises in family law at Hunters solicitors, said: “The judgment shows a greater understanding by the courts of the effects of psychological abuse and reflects the view of those living in modern-day Britain, that domestic abuse can not only be defined as physical but also emotional, financial or sexual.”

But David Challen is more critical. “Dangerous myths about victims of domestic violence who appear well put-together and are judged to be unaffected are continuously played out in open court,” he writes. Tab Morton, of the Women’s Equality party, said the case “has been a watershed for judicial understanding of coercive control”. However, she added: “It is also worth noting that it was evidence of Challen’s mental health conditions, and not the abuse which exacerbated them, which led to her murder charge being reduced. This feeds into the harmful idea that women must be either ‘mad’ or ‘bad’ to commit violence. Rather, abuse itself is a cause of mental ill-health.”

Women who experience abuse are three times as likely to develop a mental health condition than those who do not, according to research by Birmingham University published in the British Journal of Psychiatry last week.

Morton said: “Rather than pathologising abused women to rationalise their behaviour, our judicial system urgently needs to understand and address the impact of prolonged abuse itself.”

• This article was amended on 11 June 2019 to clarify the age difference between Sally Challen and Richard Challen.