there are occasional prosecutions of people for holding others in involuntary servitude. There is evidence of large scale human trafficking, which includes people brought to the US or UK for sexual slavery, farm work or as domestics (as in the above case.).
From
Wikipedia:
Instances of illegal slavery are still found periodically. The United States Department of Labor occasionally prosecutes cases against people for false imprisonment and involuntary servitude. These cases often involve illegal immigrants who are forced to work as slaves in factories to pay off a debt claimed by the people who transported them into the United States. Other cases have involved domestic workers.
There have been incidents of slavery amongst illegal immigrants working in agriculture. The Immokalee region in southern Florida, which grows most of the tomatoes eaten in the United States during the cold months, has had many cases of slavery. Since 1997, several prosecutions have resulted in over 1,000 slaves being freed.<160>
The New York Times,ABC News, and The San Francisco Chronicle, among others, have reported on child and teenage sexual slavery in the United States. There are also reports on children working in organized criminal businesses and in legitimate businesses under both humane and inhumane conditions.
In 2002, the U.S. Department of State repeated an earlier CIA estimate<164> that each year, about 50,000 women and children are brought against their will to the United States for sexual exploitation.<165> Former Secretary of State Colin Powell said that "Here and abroad, the victims of trafficking toil under inhuman conditions – in brothels, sweatshops, fields and even in private homes."