Man kept as slave in scrap yard caravan at Jersey Marine
A vulnerable man was beaten and forced by a father and son to live in "appalling conditions" at a scrap yard for two years, a court heard.
Hospital staff said he looked "like he'd come out of a concentration camp".
Anthony Baker, 49, from Jersey Marine, near Swansea, was sentenced to 10 years in prison after admitting forced or compulsory labour, and actual and grievous bodily harm.
His son Harvey, 19 was given six years in a young offenders' institution.
The teenager had admitted actual and grievous bodily harm.
"There wasn't a part of his body that had not been beaten over a period of time," said Supt Catherine Larkman, from South Wales Police, after the hearing.
"He had been systemically abused and beaten dreadfully."
The court heard the victim was 18 when Anthony Baker, of Earlswood Cottages, forced him to work for him from October 2016, with the abuse lasting until January 2019.
Prosecutor John Hipkin described how he was forced to live in a caravan at Jersey Marine and work each day from 06:00.
"He (the victim) said the beatings would happen if he didn't clear out the animals or did something wrong," said Mr Hipkin.
"One of them would bend his arms behind his back while the other would punch him repeatedly."
He described attacks happening daily, often involving a scaffolding bar and leaving the victim's appearance "permanently altered".
The court heard the victim had spent time in hospital as a result of his injuries, but lied to medical staff.
On one occasion he told doctors he had been "kicked by a horse", but later told police Harvey Baker had punched him "so hard it felt like his eardrum burst".
"He was allowed to visit his mother over Christmas. On his return Harvey Baker said he looked tired, and he was given a beating," said Mr Hipkin.
The victim received one meal a day, which consisted of tinned soup, baked beans or gone-off food from a bakery.
When police found him, after being tipped off by concerned neighbours, "he was struggling to speak due to fractures to his jaw", Mr Hipkin added.
Judge Paul Thomas described the defendants' behaviour as "sadistic" and said the victim would never "fully recover from what happened to him".
"It would have been utterly appalling if you'd treated any of your animals the way you treated him - let alone a teenager," he said.
"You kept him hungry and thirsty, he had to live in conditions that were not fit for human habitation.
"Between you, you hit him with anything that came to hand, scaffolding poles, Hoover pipes, knives.
"I have seen the photographs and they are chilling."
Acting Det Sgt Heather Southway said: "In all my years' service it has been one of the most emotionally impactive cases I have dealt with.
"The defendants have shown no remorse for their actions in targeting a young and vulnerable victim."
She described the victim as "living in squalor", adding: "It is unbelievable that two people could treat another human in this way."
The force's lead for modern slavery, Jonathan Drake, said it was not limited to cities or industrial areas but "could be taking place on any street in the UK".
"Modern day slavery is an incredibly complex crime to unravel and it is vital that we increase the eyes and ears capable of recognising the signs of symptoms," he added.
"It is often referred to as a 'hidden crime'.
"Victims often do not perceive themselves as being victims, or may be unwilling to seek help."
The Crown Prosecution Service's Iwan Jenkins said the father and son had taken "advantage of his vulnerability" and "fed him only tins of food as a result of his work".
"They used violence against him to ensure that he continued that work. He was in fear," he added.
"No payment was offered."