Britain’s Home Office said that there could be up to 13,000 victims of slavery in the country, far more than previous estimates, media reported .

Modern slavery victims are said to include women forced into prostitution, “imprisoned” domestic staff and workers in fields, factories and fishing boats, BBC reported.

The Home Office has launched a strategy to help tackle slavery.

It says the victims include people trafficked from more than 100 countries – the most prevalent being Albania, Nigeria, Vietnam and Romania – as well as British-born adults and children.

Data from the National Crime Agency’s Human Trafficking Centre last year put the number of slavery victims in Britain at 2,744.

The Home Office said that the Border Force would deploy specialist trafficking teams at major ports and airports to spot potential victims, and the legal framework would be strengthened for confiscating the proceeds of crime.

The Home Office said that it used established statistical methodology and models from other public policy contexts to estimate a “dark figure” that may not have come to the National Crime Agency’s attention.

The Home Office said the “tentative conclusions” of its analysis is that the number of victims is higher than thought.