The full horror of human trafficking was brought home to Luton documentary maker Zakir Hossain, 42, when he was asked to make a film on the subject.
It was commissioned by American government agency USAID, started by former President John F Kennedy to end global poverty.
The father-of-two, who lives in Colin Road, has now written a novel based on his experience. It is called In the Shadow of the Red Light: A multifaceted documentary-novel on global sex trade.
He said: “We call ourselves civilized. We build skyscrapers and travel to other planets while this vast, illicit, multi-million-pound industry simply carries on.
“One of the vicious consequences is the sex trade where women are enslaved, raped, tortured and forced into having sex 20 to 30 times a day.
“Human beings are sold, displayed, auctioned, smuggled and trafficked – they are a profitable commodity.
“I did not have any direct understanding of this modern-day slavery until I was given the assignment.
“As I did the research, I came to know the unbearable suffering of women and children caused by heartless, devil-like traders.
“They often end up with incurable diseases like HIV. And finally they are thrown away when their bodies are no longer marketable.”
In 2008, Zakir was commissioned to make a drama-documentary on sex trafficking for the South Asia Foundation.
And once again he found himself immersed in research.
He recalled: “I looked at all sorts of material from various sources, read case studies and interviewed many victims who had been rescued from brothels in India and Pakistan.
“I also interviewed children who had been trafficked and I used all of this as background for my novel.”
He added: “Hundreds of documentaries have been made by film-makers like me. There have been many articles, novels, news stories, seminars and conferences. But human trafficking hasn’t stopped.
“It is as old as human history. Weaker members of society are always victimised, used and abused.
“‘Might is right’ was the motto in primitive times: it is even truer today.
“We have a long way to go to end this evil trade. My book is one more serious effort towards that goal.”