Lesley Dunford, 37, maintained her innocence after being jailed for seven years for the manslaughter of three-year-old Lucy after she suffocated her.
But her husband Wayne stood by her believing she was a victim of a miscarriage of justice.
But while in prison she admitted pushing seven-month-old Harley’s face into his cot mattress when she couldn’t stop him crying at the family’s former home in Camber, East Sussex.
Today, Justice Jeremy Baker, sitting at the Old Bailey, sentenced her to life with a minimum term of 13 years after hearing that her soon to be ex-husband, forgives her.
He said: “The reality is had you not confessed to having killed Harley whilst in custody it’s highly likely there would not have been a police investigation into his death and you would not have faced prosecution for his murder.”
Dunford, wearing glasses and her hair tied in a pony tail, appeared emotionless as she was jailed and at times rocked back and forth in the dock as she heard the details of the murder.
Philippa McAtasney QC, for the prosecution, said: “She did this, the prosecution says, by deliberately suffocating him.”
The court heard, at 3.10pm on the day of Lucy’s death on February 2, 2004, six months after Harley’s death, she ran to her vicar Lucy Murdoch, who had been consoling her, and said ‘it’s happened again’.
Miss McAtasney said: “She was said by hospital staff to be behaving oddly and saying inappropriate things.
“No action was taken against her in response to the second child.”
Harley had been found dead in his cot on August 27, 2003, and a finding of death by staphylococcus pneumonia infection was initially wrongly recorded in the post-mortem.
But a post-mortem revealed Lucy died from asphyxia due to forced blockage of her airways.
A 2009 inquest into Lucy’s death prompted police to reinvestingate and charge the mother with murdering Lucy, which she denied.
Dunford was jailed for seven years at Lewes Crown Court for Lucy’s death after being convicted of manslaughter in June, 2012.
Miss AcAtasney said: “She’s currently serving that sentence. Whilst she has been in custody new evidence came to light when this defendant began to make admissions to killing her son.
“She had also then admitted killing Lucy.
“Mrs Dunford said ‘I did it. I killed him. I killed the baby’.
“She said she was having nightmares with flashbacks.
“She said she hit Lucy against the headboard or wall then suffocated her.
“She said ‘All I want is to be punished and be with my children’.
“She said ‘I keep having flashbacks, I can’t sleep. I keep reliving the day when he died.’
“She said she loved her children and she shouldn’t have done it.”
She then wrote a handwritten confession from Drake Hall prison in Staffordshire in June, 2014.
It read: “I remember the day very clearly. At the time I put Harley to bed.
“He had been given his breakfast.
“I was settling him down in his cot. I left him in his cot.
“He kept crying.
“I went back into the room, went over to his cot and pushed his face into the mattress until he stopped breathing.
“Then I titled his head back to the side and notice he had foam at the mouth and blood out of his nose. That was when I knew I had really hurt him.
“I didn’t know why I had done it.
“I relive it every day. I know what I did was wrong and I deserve to be punished.
“I shouldn’t have done it and I will have to live with it for the rest of my life. I’m really sorry to the people I have hurt.”
A review of the post-mortem found Lucy’s death was consistent with the mother’s explanation.
The pair have a third child who is currently in care and cannot be identified for legal reasons.
Alan Kent QC, in mitigation, said: “She has a very low intelligence and has complex mental health problems.
“She confessed during the course of her prison sentence at around the time her husband was divorcing her.
“He says that although he’s currently divorcing her he wishes her the best for the future.
“He says she needs to be given all the help she needs to deal with her mental health issues she has.
“Describing his soon-to-be former wife he says she’s a gullible person who is easily taken advantage of.
“He, the father of those children, forgives her.”
Mr Dunford, 58 who now lives in Exeter, Devon, continued to live as her husband for nearly a decade not knowing she had killed their children.
He stuck by her believing her first conviction as wrongful but was devastated when she admitted murder.
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