The man, who has asked to remain anonymous has revealed how he was forced to work or face being beaten badly, was kept outside in the rain and had to go to the toilet in the woods.
He has spoken as figures released to the Yorkshire Post show there were 121 reports of modern day slavery made by West Yorkshire Police in 2018 - a 40 per cent increase on the previous 12 months.
These include 73 adults and 48 children.
The man, who was homeless and vulnerable, said: "They forced me to dig out driveways ready for block paving and tarmacing, and if I didn't work I got beaten up.
"I was living in a trailer with no windows in it, no door, and every time it rained I got wet.
"There wasn't any facilities for people to have a wash so we used to have to get a wash with cold water.
"If I needed the toilet I had to use the woods or go somewhere else.
"It affected me a lot, because they were taking money off me and I swore I'd never go back to that sort of living. "
He said: "I hope it doesn't happen to any of the homeless that are about now, they can seek help from the local government and that.
"If they don't they are going to end up how I did over 15 years and I have known some of them to be there longer than what I have.
The man is currently being supported in West Yorkshire by the Palm Cove Society which provides emergency accommodation for victims of modern slavery,
He said: "They have helped me sort my money out and they've helped me with all my bills.
"They have sorted out a place for me to live.
"Now I am doing my own shopping and paying my own bills. I am also buying myself new clothes.
"Without their help I wouldn't be here now."
The man has spoken to West Yorkshire Police and Crime Commissioner Mark Burns-Williamson to help raise awareness of modern day slavery.
Mr Burns-Williamson said: “It’s hard to comprehend both the horrendous situation this survivor has been through and simply how anyone could treat another human being in this manner.
“Hearing this survivors story makes me even more determined, as the national lead Police and Crime Commissioner on modern slavery, to safeguard the victims and survivors of this horrific abuse and bring the perpetrators to justice."
“It is pleasing to know that the survivor is now safe and being support by a fantastic organisation, the Palm Cove Society, who have enabled him to rebuild his life and live independently.
“Working with partners, such as the Palm Cove Society, we are continuing to see progress both in West Yorkshire and nationally across all areas in tackling human trafficking and modern slavery which is a key priority in my Police and Crime Plan, but we know there is always more to do.”
People are also urged to look out for general indicators of human trafficking or modern slavery.
Mr Burns-Williamson said: "Our communities continue to have a key role to play in stopping this from happening.
"We need you to support any suspicions, no matter how small, to the Modern Slavery Helpline or to the police.
Detective Chief Inspector Helen Steele of West Yorkshire Police, paid tribute to the man who came forward to police and relived his horrific ordeal.
She said: “His bravery is helping to raise awareness of this awful crime that often hides in ‘plain sight’.
"It could be happening on your street or in your workplace but by knowing how to spot the signs – which these videos highlight people can help us to rescue victims and bring offenders to justice.”
Yvonne Hall, Managing Director of Palm Cove Society, said: “I am delighted that the eradication of modern slavery continues to be one of the PCC's priorities. This promotes continued awareness raising within our communities.
“As an organisation, we work tirelessly with partners to ensure that identified victims and survivors of modern slavery are safeguarded and well supported. This is a crime that is often 'hidden in plain sight' and communities must be vigilant.”