Making sense of their childhood years has been a life's work for Sally Challen's sons. For while they have never believed their father Richard deserved to die, they do understand why their mother was driven to kill him.
The 65-year-old mother-of-two saw her conviction for murdering her husband of 31 years by hitting him 20 times with a hammer quashed at the Royal Courts of Justice today.
She now faces a retrial after a panel of judges at the Court of Appeal ruled she was suffering from two mental disorders at the time of the 2010 attack. She has already served eight years in a Surrey prison.
Behind today's watershed moment is a tale of extraordinary filial love and a heroic fight for justice by the two level-headed young sons who emerged from the Challens' ill-fated marriage.
Challen, right, 65, was jailed for 22 years for murdering her husband Richard, left, 61, with a hammer in August 2010 but her sons David, 31, and James, 35, claim she was the victim of decades of abuse including rape and psychological torment by their father
Richard Challen with couple's son David as a child, centre, and his brother James
There is little doubt that 31-year-old David and his brother James, 35, have been her most powerful allies in winning over public opinion and gathering support for her case.
Even more remarkable is that they have thrown their support behind their mother while respecting the memory of their father, who was 61 when he died.
Or as David put it in an exclusive interview with the Mail last October: 'We do not justify our father's killing. We are seeking to stop the lie that our mother is a murderer.'
But it has taken years of dedication by a young man who juggles his job with a film distribution company while campaigning against domestic violence with the group Justice For Women and addressing feminist conferences around the UK.
Even after the 'deep shock' of seeing their mother found guilty at Guildford Crown Court in 2011 and sentenced to life imprisonment, they refused to give up their quest.
Shortly after the 2011 conviction, the family contacted Justice For Women, a feminist law reform campaign group which supports women who have killed their partners as a response to domestic violence.
Police guarding the couple's property in Claygate where Richard Challen was bludgeoned to death with a hammer by his wife Sally
Sally Challen's case, however, is the first of its kind because although she says she was raped she was not a victim of sustained and persistent physical violence. The abuse her supporters say she suffered was largely psychological, financial and emotional. They say Richard's behaviour pushed her to the brink.
'We have had a lifetime of living with this and eight years trying to find the words,' David said this week.
The words he is referring to are 'coercive control', a legal term which ultimately enabled the brothers to articulate what they say their mother had suffered at the hands of their father, which wasn't the kind of physical violence usually associated with domestic abuse cases but something far more psychological.
The Serious Crime Act 2015 created a new offence of controlling and coercive behaviour in an intimate or family relationship, recognising that a pattern of isolation, humiliation and domination could rob women of their lives as much as physical violence, and was a form of domestic abuse.
It was on these legal grounds that Mrs Challen was given leave to appeal against her murder conviction in 2011 when 'coercive control' wasn't recognised by the law.
At her trial the prosecution said Challen, pictured left on her wedding day and right with her husband, was driven by jealousy over possible infidelity
Right from the moment in August 2010 that his family life was torn apart, David has felt only compassion for his mother.
He was 22 at the time she killed his father – she hit Richard Challen over the head with a hammer more than 20 times while he ate the bacon and eggs he had made her go out in the rain to buy that morning.
She wrapped his body in a curtain and left a note on it saying: 'I love you' before washing the dishes and leaving the £1 million marital home in Claygate, Surrey.
Sally Challen, pictured, has had her murder conviction overturned after a landmark appeal that saw her argue she
