In 2010, Sally Challen battered her husband to death with a hammer after years of being psychologically and physically abused by him.
He controlled every aspect of her life – refusing to let her keep her salary, belittling her appearance, and raping her.
When she finally snapped, she spent nine years in prison for his murder.
But in 2015 the law changed, making “coercive control” an offence. In a landmark case, in which she was supported by her two sons, Mrs Challen appealed her conviction and finally walked free in June this year.
We’ve been talking to her about her experiences, and began by asking her to say what exactly coercive control meant.