A man was housed in a caravan with no running water or toilet while employed by a person nicknamed The Tank Commander, a court heard.
James Keith was a homeless teenager in the 1990s before he was taken off the streets and offered work.
The original meeting occurred outside a pub at Glasgow’s Barras Market.
Mr Keith, who is now 41, went on to meet Robert McPhee and his family while staying at a number of travellers sites across Scotland.
McPhee got Mr Keith to help carry out jobs such as mono-blocking driveways. But, he said he ended up feeling “owned” and allegedly suffered beatings when he tried to escape.
Jurors heard claims McPhee’s son James later told Mr Keith that he had “bought” him from his father and could only leave for “a few grand”.
The witness recalled: “You had no option, but to go back. You did not get an option.”
The accusations were yesterday made at the High Court in Glasgow.
Robert McPhee, 65, James McPhee, 45, Steven McPhee, 37, and John Miller, 38, face a total of 30 charges between them. The allegations – which span from 1992 to 2016 – include slavery and violence. The four deny all the charges.
Mr Keith was yesterday the first witness to testify. He recalled being homeless aged 16 when he was approached by a man and asked was he looking for work.
Mr Keith ended up being taken to a travellers site close to the nearby Gallowgate. It was there he met Robert McPhee, who he got to know as Bobby. Mr Keith said his nickname was Tank Commander.
The witness stayed in a caravan that had no water or toilet meaning he had to use the facilities at a local cafe.
He started working for McPhee before moving to different sites in Glasgow including in the Hillington and Maryhill areas. At one stage, Mr Keith had to sleep in the front of a truck. They also moved to Larkhall, South Lanarkshire and Bathgate, West Lothian.
The court heard Mr Keith first tried to leave while staying at the site in Maryhill. He went to a hostel, but told jurors he was “captured”.
The witness said he did not have cash and that he felt like a “bit of property”.
Mr Keith told the court that on an occasion in Bathgate he was stripped and locked in a shed by James McPhee after being out drinking.
The trial continues.