A mother has been found guilty of battering her "helpless and vulnerable" baby daughter to death two hours after social workers left her home alone with the child.
Jennifer Crichton, 35, left her seven-month-old daughter Amelia with "catastrophic" head injuries, including bleeding on the brain, in her right eye and a fractured skull.
She was allowed to keep seven-month-old daughter Amelia, under a social service care plan devised by Lancashire County Council and outsourced to a local social care provider.
Asked by her social worker to take over feeding of the baby Crichton replied: "No, you do it," and went for a cigarette instead, a jury at Preston Crown Court heard.
Later that night the social worker left her alone with the child and within two hours Crichton had attacked Amelia at the family home on Slater Lane, Leyland.
The defendant had denied murder and tried to blame the child's father, Richard Sheppard, who today spoke of his devastation.
A jury of nine men and three women, who heard five weeks of evidence, convicted her in under two hours on Tuesday morning.
She will be sentenced at a later date.
Outside court, Mr Sheppard said: "I'm happy and shocked and sad. This has destroyed my life. She tried fitting me up."
Amelia's grandmother Sally Quested said: "Amelia fought really hard for life only for her mother to take it away from her."
They say the defendant wanted Amelia only as a "meal ticket" to get a house.
The child, born "on the cusp of life" at 24 weeks, and weighing just 570 grams, had spent six months in intensive care due to her prematurity.
But after discharge she behaved like a normal baby, going home to live with the defendant under a "care plan" with the help of support workers who stayed overnight at the address until the hours were reduced over time.
Around 6pm on April 19 last year, a care support worker arrived at Crichton's home.
During the evening when the support worker suggested Crichton take over feeding the child, the mother replied: "No, you do it," and went outside for a cigarette.
At 11pm the care worker left and Amelia appeared to be fine, until, an hour and 20 minutes later, Crichton rang 999 for an ambulance.
Paramedics managed to resuscitate Amelia on her way to the Royal Preston Hospital, but she was then immediately transferred to the Royal Manchester Children's Hospital for specialist treatment.
Crichton offered no explanation for her daughter's injuries, other than to say she had "collapsed", even as doctors battled to save her life.
Two days later, doctors concluded Amelia would not recover from her "catastrophic" brain injuries and further life support was withdrawn at 8.15pm on April 21 last year, with the child declared dead 20 minutes later.
Medical experts concluded she had been the subject of a "violent physical assault" immediately before her collapse as a result of "striking or throwing" against a hard surface, as well as bodily shaking.
Amelia's injuries included bleeding to the brain, damage to nerve fibres in the brain stem, a complex skull fracture to the right side of her skull and bleeding to her right eye.
Crichton faces a mandatory life sentence for murder, with the minimum term to be set after the judge hears the results of a psychiatric report on the defendant.