It’s not uncommon for a victim of sex trafficking to be raped by 90 men in the course of one weekend. Although 30 men in one day would probably be more likely.

Emma Foster (not her real name) reports these facts with little emotion. She’s a trustee of the Purple Teardrop charity whose main job is to raise awareness and help those rescued from sexual slavery.

It seems ironic that we meet at her east Dorset home as the world heaps praise on the Oscar-nominated ‘Twelve Years A Slave’, which depicts the horrors of two centuries ago, when equal horrors are taking place this very day. Emma agrees.

“I think many people believe that slavery can’t exist anymore but it does,” she says.

Purple Teardrop got going with the support of Soroptimist International, a meeting group for professional and business women. They don’t take part in slave rescue but do raise money to help those who fall victim to this trade.

“One study worked out that one girl could be worth £150,000 a year to a trafficker,” says Emma.

“That wouldn’t be for many years, because they would outlive their usefulness, they are often drugged and because of what happens don’t live very long lives.”

And naturally this high value attracts violent crime as traffickers will do anything to gain and hold onto their assets, hence Emma’s request for anonymity.

Because of its secretive and criminal nature, solid figures are hard to come by although the International Labour Association estimates that 21 million people worldwide are living in forced labour, with 270,000 victims of sexual exploitation in Europe alone.

However, says Emma, police know that victims trafficked from abroad arrive here in a variety of ways.

“Sometimes the women are sent by their families who believe they are going to get a good job, they can come from rather innocent countries so they take what they are told at face value in a way that we might think twice about.”

In the past women were literally bundled off the streets of their home country and crated here. Now they may be coming in with a passport, convinced they are starting a new life.

“Once they’ve gone through customs they are free and that’s it, they are picked up from the airport,” says Emma.

“Apparently there used to be a cafe at one of London’s airports where the chances were, if you saw two men sitting there with a young girl in between them, she wouldn’t know they would be negotiating to sell her.”

This is spine-chilling but it is only when slaves arrive at their final destination that the real nightmare begins; beatings, force-fed drugs and: “The average number of times per year she will be forced to have sex is probably around 4,000,” says Emma.

It’s worth pointing out at this juncture that men who have sex with trafficked women are committing rape and if the girl is underage, claiming not to know this would be no defence in court.

However, Emma says: “I may be wrong but I believe that most men, even if they chose to use a prostitute for whatever reason of their own, wouldn’t do it if they knew the woman was there against her will and they would report it. It’s easy enough, you can call Crimestoppers which is totally anonymous.”

She also wants Echo readers to look out for signs of trafficking because: “It could be happening on your street, typically the traffickers will rent a small house in a residential area and there will probably be one girl enslaved there.”

Men coming and going, curtains shut in the daytime, little sign of the occupants could indicate potential trafficking and Emma wants landlords and estate agents to help spot this kind of illegal activity.

Workers such as postmen or milkmen are asked to keep a lookout, too.

She shows me a picture of a room in a Boscombe house from which a trafficked girl was rescued.

It’s a depressing scene of condoms, toilet roll tissues, and, on the cheap pink bed, a child’s nightdress case, stuffed – it was later discovered – with money earned by the girl which she would never have received.

It’s a shocking image but one which could apply to any number of residences in this area.

Rescuing the girls is hard; they are terrified of being killed, or harm coming to their families and: “They are suffering with post traumatic stress disorder.”

They are moved to safe houses away from the area they were incarcerated.

And then the real work of Purple Teardrop begins, providing funds for extras such as college equipment so they can become skilled and educated.

“We provide items like local maps and palm-top translators, small, basic things so they don’t get lost and which help them get around.”

While looking forward to Home Secretary Theresa May’s Modern Slavery Bill, they are also petitioning for a parliamentary debate on the banning of ‘sex for sale’ advertising.

It seems it cannot come soon enough. Because, says Emma, they are now getting firm reports of trafficking taking place within the UK, with girls being groomed, and on at least one occasion, snatched, to join this loathsome trade.

As I leave Emma’s home she guesses what I’m thinking.

“Yes, they could even be in this street,” she says.