South Yorkshire Police has admitted failings after a Wath man hit over the head with a metal pole was left in a cell for ten hours without medical treatment.
Dean Hutton suffered serious brain damage in an attack by brothers Brett and James Garbutt in Rotherham in 2009 but was arrested and taken to a police station, where he was dismissed as drunk.
The 26-year-old, who now needs lifelong care, has taken the next step in his battle for justice as the police admitted their failure to get him treatment sooner led to his further suffering.
Paramedics checked Dean at the scene but when police arrived they arrested him for missing a traffic offence court appearance and he was taken to the station and put in a cell.
It was only after his condition deteriorated over ten hours that he was eventually taken to hospital, where it emerged he had a fractured skull and bleeding to his brain.
His parents launched a fight for compensation to provide Dean with rehabilitation treatment and lifelong care, and police chiefs initially denied responsibility.
But the force has now admitted liability out of court after medical experts said Dean would have made a full recovery had he received medical treatment earlier.
His father, Roy, 59, said before Dean's brain injury, he was completely independent but now needs help with almost everything he does.
"When we first heard about the brain injury we were so worried and we prepared for the worst. But Dean is battling back and his rehabilitation has helped him come a long way.
"He is now attending college and we are just relieved the police have admitted responsibility, meaning we don't have to go to a full trial and that we should be able to access the care and rehabilitation Dean will need for the rest of his life.
"We are angry Dean's injury was not accounted for and so dealt with by police officers sooner."
A compensation hearing will be held at a later date to determine how much money the family should receive.
Dean currently receives specialist rehabilitation and physiotherapy and needs support with daily activities.
He also attends Dearne Valley College three times a week to study maths, English and IT. His attackers, were found guilty of grievous bodily harm with intent at Sheffield Crown Court and were jailed for seven years, five months and five years.