Slavery has made a "horrific" return to modern Britain, the most wide-ranging study of the secret world of forced labor yet published showed.
Shocking statistics about the country's sex trade, including an estimated 5,000 under-16s coerced into prostitution, masked equally violence-ridden and illegal practices in jobs ranging from crop-picking and factory work to nursing and the catering trade.
Victims were now in the tens of thousands, the report by researchers at Hull University, commissioned by the Joseph Rowntree Foundation, showed.
It said that parts of the economy depended on slave labor, in the same way that 18th century businesses [like sugar] profited from the "triangular trade'' between West Africa, the Caribbean and western Europe.
"We are not devaluing an emotive word," said Professor Gary Craig, associate director of the Wilberforce Institute for the study of Slavery and Emancipation at Hull. "The shackles may not always be physical, although I have no doubt that in some cases they are. Debt bondage, theft of passports and ID, and threats of violence are tools of slavery."
The report detailed case after case where conditions contravened the UN's 10-point definition of forced labor.
Craig and co-author Aidan McQuade, director of Anti-Slavery International, said a huge percentage also meet the three definitions of modern slavery: extreme economic exploitation, absence of human rights and actual or threatened violence.
Documented instances included two Vietnamese men who paid ?18,000 (US$35,000) to an agent in Vietnam for London hotel jobs, came to Britain legally for work agreed at ?4.95 an hour, but subsequently had their passports taken by the agent's British counterpart and were given food only for two months.
When they protested, their families in Vietnam were threatened with violence.
A woman from Latvia had her passport confiscated by a Hull agency which forced her to work 16-hour shifts at a factory, sleeping between them in a car. A couple from eastern Europe paid another Yorkshire agency ?250 for an "introduction to work'' in the Humber port of Goole, where they were underpaid and slept in a dormitory shared with eight men.
The findings were endorsed by Archbishop Desmond Tutu, who said he was shocked by the spread of slavery.
"I just didn't know about all these forms that exist. It is hidden. Generally people would not believe that it is possible under modern conditions," he said.