When the infant known in court only as Baby P was brought home from hospital days after his birth in March 2006, it was as a bubbly, blue-eyed boy with the first signs of curly blond hair. He was, according to those who came into contact with him, a lively child with a ready smile.

After 17 months enduring abuse of an almost unimaginable cruelty, the boy had been reduced to a nervous wreck, his hair shaved to the scalp and his body covered in bruises and scabs. Physical injuries included eight broken ribs, a broken back and the missing top of a finger, while the emotional damage was almost incalculable. Despite it all, Baby P was said to have still attempted a smile.

The jury was told that details of the intervening months, leading to the baby’s death last August, would “fill [them] with revulsion”. But even this could not prepare jurors — one of whom could not hold back tears — for one of the worst cases of sadistic brutality and sordid child neglect to come before a British court.

Baby P’s life in a council flat in Haringey, North London, began with gradual and growing neglect at the hands of his mother, who would leave him unattended for hours in his cot. The overweight woman, who had never had a full-time job and spent hours trawling the internet for pornography, split from the boy’s natural father when he was 3 months old after affairs with two men.

When the second lover moved in, Baby P’s suffering increased dramatically. The court heard that while his mother gossiped with friends in online chat rooms, her boyfriend took to beating the boy, swinging him around by the neck or legs and pinching him.

The Times has been told that the man, who cannot be identified for legal reasons, forced Baby P to follow commands like a dog. At the click of a finger he would have to sit with his head bent between his legs; 20 minutes later a second click would be the signal that he could sit upright again.

A second man, Jason Owen, also subjected the boy to similar abuse. Owen, who stayed at the house for five weeks with his 15-year-old girlfriend, was found guilty with the boyfriend of causing or allowing the death of a child. The mother admitted her guilt at an earlier hearing.

Police were told that the boyfriend, a 32-year-old collector of Nazi memorabilia, wanted to “toughen him up”. Other routines included placing the baby on a stool and spinning it around until he fell off.

The authorities had first voiced concerns about possible abuse by October 2006, when a GP noticed marks on the boy. But his mother, in the first of many episodes of deception and false reassurances, insisted she had found that his skin “bruised easily”.

Two months later the GP sent the pair to the Whittington Hospital, North London, after inspecting a head injury. Insisting that her child was “a head-banger” fond of “rough and tumble play”, the mother claimed that fingermarks were merely the result of when he was caught after being lovingly held and thrown into the air.

Social services were informed and visited the flat, which was found to be dirty, untidy and smelling of urine. They learnt that it was shared with the boy’s grandmother and three dogs, including a rottweiler, but remained unaware that it also harboured a violent boyfriend. They decided to let the child stay with a family friend while police inquiries continued.

A month later, in January 2007, with no decision made on any charge against either woman, the boy was allowed back home. As he grew too old for milk and jars of baby food, Baby P scavenged bits of broken biscuits from older children and was even seen eating dirt in the garden. Detectives found that after the boyfriend moved in there was not one piece of the boy’s clothing that was not spattered with blood.

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