The trust which runs the Kent and Canterbury Hospital is facing a compensation payout for millions after a couple discovered that medical negligence is responsible for their son's severe autism.
Ben Harman's parents had believed their son's condition was a cruel accident of birth and only discovered the truth when they applied for a disabled parking badge.
They learned medics had failed to diagnose "catastrophically low" blood sugar levels after Ben's birth in 2002.
Ben, who is now 13, was eventually given dextrose, but it came too late to save him from devastating brain damage and autism.
Mr Justice Turner told the High Court: "When he was discharged, his parents were told nothing about the risk that his low blood sugar levels may have caused lasting damage."
His parents were deeply worried when he failed to meet his milestones, but had no suspicions that he may have been a victim of medical negligence.
The judge said that it was in 2006 that the couple applied for a blue badge so that they could park their car in disabled bays.
He added that the truth was "only revealed incidentally" when the couple were asked for medical evidence in support of their application.
Ben's mother, Joanne Harman, finally sued and the East Kent Hospitals University NHS Foundation Trust admitted liability in July 2013.
Now, following the judge's ruling, Ben is in line for massive damages to fund the lifetime of care he will need.
The trust will have to pay his fees at specialist boarding school, Prior's Court, in Hermitage, Berkshire, until he is 25 and, thereafter, fund his care regime at home.
His parents, originally from Kent, are currently renting a large house, in Marlow, Bucks, so they can be close to him.
"He is prone to having unpredictable tantrums and can lash out physically while shrieking at the top of his voice. There is a real and continuing risk of injury to himself and to others..." - Mr Justice Turner
The judge said Ben's thinking skills are seriously impaired and he has the oral communication skills of a six-month-old baby.
His social awareness is only a little higher than that and he struggles to meaningfully relate to others.
"He is prone to having unpredictable tantrums and can lash out physically while shrieking at the top of his voice," the judge added.
"There is a real and continuing risk of injury to himself and to others" and, as he grows older and bigger, his care has become more and more challenging.
His parents had fought tirelessly for local authority funding so that he could attend Prior's Court, a world leader in educating autistic pupils.
By the time he got in his parents were "at the end of their tether, exhausted by the physical and emotional challenges of looking after him".
The judge said Ben was thriving at the boarding school and goes home for school holidays and every other weekend.
"He has only now started to hug his mother", the judge said, adding that the family had recently taken their first foreign holiday for 10 years.
His parents were determined to welcome him back home when he leaves school at 25, the court heard.
And the judge rejected the Canterbury-based trust's arguments that he would be better off spending his life in institutional care.
The amount of the Ben's compensation has yet to be finally calculated, but it is bound to be a high, seven-figure, sum.
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