Up to 13,000 modern-day slaves could be trapped in the United Kingdom, according to an analysis by the Home Office.

There are between 10,000 and 13,000 imprisoned domestic staff, women forced into prostitution, and agricultural and factory workers.That number also includes trafficked men, women and children in the U.K., according to the Independent.

This is the first time the government has officially recognized the situation, BBC reported.

The Home Office said the victims included people trafficked from more than 100 countries, but the highest populations hail from Albania, Nigeria, Vietnam and Romania, in addition to the British-born adults and children.

The National Crime Agency's Human Trafficking Centre had a far lower number last year, reporting only 2,744.

Home Secretary Theresa May said the number was shocking.

"The first step to eradicating the scourge of modern slavery is acknowledging and confronting its existence," she told The Guardian. "The estimated scale of the problem in modern Britain is shocking and these new figures starkly reinforce the case for urgent action."

Professor Bernard Silverman, the chief scientific adviser to the Home Office, and modern slavery minister Karen Bradley, both said the problem with the numbers is that modern slavery is hidden more deeply than previous types of slavery.

"Modern slavery is very often deeply hidden and so it is a great challenge to assess its scale," Silverman said. "The data collected is inevitably incomplete and, in addition, has to be very carefully handled because of its sensitivity."

Part of the solution is educating the general public on what the signs are, so that residents can be on the lookout for such activity in their neighborhoods and towns.

Lawmakers are also doing their part with a bill currently going through Parliament to provide courts in England and Wales the power to protect people who are trafficked, BBC reported. Scotland and Northern Ireland are also planning similar measures.