LONDON: Feted for playing an FBI agent in "The X-Files" tackling the supernatural, actress Gillian Anderson has cast herself in the real-life role of an anti-slavery campaigner after being shocked at the scale of the problem.

Anderson said she had been unaware up to 46 million people globally were living as slaves, generating an estimated $150 billion in illegal profits a year, until she became involved in the film "Sold".

Based on a book about a Nepali girl trapped in the sex trade, "Sold" follows 13-year-old Lakshmi as she fights to escape the red-light district of Kolkata, India.

In the film Anderson's role is inspired by real-life US photographer, Lisa Kristine, known for documenting victims of modern day slavery trafficked into forced labour, sold for sex, trapped in debt bondage or born into servitude.

The film is being screened in London on Wednesday at Trust Women, an annual women's rights and trafficking conference run by the Thomson Reuters Foundation.

Describing slavery as a pandemic, Anderson said it was shocking that so many people are living as slaves today in every country across the globe, from India to the United States.

"At certain points in one's life one realises there are issues that break your heart," Anderson, 48, told the Thomson Reuters Foundation in an interview.

"I've been involved in many charities over the years but the issue of trafficking, particularly child trafficking for sex, is such an abomination of humanity that I cannot not do something."

SEX TRAFFICKING THRIVING

The American actress, who has three children aged from 22 to eight, said it was unacceptable that an estimated 1.8 million children were trafficked into the sex trade every year.

Globally, nearly 21 million people are victims of human trafficking, according to the International Labour Organisation.

Of that total, an estimated 4.5 million people are forced into sex work, despite the fact international law and the laws of 134 countries criminalise sex trafficking. Women and girls make up an estimated 98 percent of victims of sex trafficking.

"It is the fastest growing black market industry in the world. It is easier sometimes to traffic humans than to traffic drugs," said Anderson.

"The film is an entry point to the issue. By telling one girl's story it gives voice to the millions of children who are trafficked every year."

Anderson, who lives in London, said she hoped "Sold", set for a digital release early next year after limited theatrical screenings since 2014, would help raise awareness of the issue.

It is being backed by a campaign TaughtNotTrafficked, which is lobbying for children to have access to an education.

She said governments did not appear to know how to start to combat trafficking which was "an intricately woven web", while companies needed to be involved to clean up their supply chains.

"Funds and action and time and resources and a different structuring of policing - a lot needs to take place in order for this to change and it has to become a priority," said Anderson.

"It affects all of us even though we might not realise it. It is in every city, in every country ... and we need to start the conversation about what we can do to make changes ."

Anderson said the revival of her role as Dana Scully in "The X-Files" this year for a 10th season after a 14-year gap may have helped draw some attention to her campaign work.

"I am not a big social media person but there was something about being wrapped up in that series again that initiated more activity from me," said Anderson who has just finished two films, "Crooked House" and "Viceroy's House", for 2017 release.

"In that sense maybe more people would have become aware of the fact that I am part of a campaign to end slavery."

Does that mean an 11th season of the popular science fiction TV series is around the corner?

"Probably not. I think it is finished," she said.