As Paul O'Neil began a minimum 22-year jail term for murdering his son Aaron, it emerged that social services and health staff had known he posed a risk to children but did little to intervene.
Social services had looked into the jobless father-of-six's violent past in May 2004, nine months before he killed his three-month-old son.
They completed an initial child protection assessment "because of concerns raised in relation to father's capacity for violent behaviour and the risks he may present to the mother and her unborn child."
But not enough was done to ensure that Aaron was protected from a sadistic father who had been physically violent to his former partners and abusive to his five other children - something social services admitted today.
O'Neil, 33, held his son's face against a gas fire for at least 10 seconds, causing horrific burns.
Four days later - after drinking and smoking cannabis - he inflicted the final fatal injury to the tiny baby by shaking him and fracturing his skull by a blow to the head.
A post-mortem examination revealed there were 37 separate injuries and marks on Aaron's body.
He had suffered a shocking catalogue of non-accidental burns, bruises and broken bones during his life, which ended violently on February 10 last year.
Some of the injuries, among them a healing skull fracture, were inflicted days or weeks earlier, Newcastle Crown Court heard.
There was also evidence of a cigarette burn on Aaron's shoulder and a scalding injury.
Health visitors and social services had tried to keep a check on Aaron but O'Neil and the baby's mother, Jodie Taylor, had stopped them from seeing the child.
Instead of demanding to see Aaron at his home in Banbury Road, Kenton, Newcastle upon Tyne, they left without checking on the tot - despite knowing about O'Neil's violent past and the fact that Taylor's first child had been taken into care when she was 14.
The court heard O'Neil had used "unforgivable violence" against his son because he resented the attention the youngster was getting from his 21-year-old mother.
O'Neil had admitted cruelty but denied murder and five charges of grievous bodily harm with intent between November 2004 and February 2005.
The jury convicted him of murder and holding Aaron's head against a gas fire but cleared him of one count of GBH. The panel of eight men and four women failed to reach a verdict on the three other counts, which were ordered to stay on file.
He was also sentenced to 14 years for GBH and five years for cruelty - both to run concurrently to the life sentence.