"Ivana" from Ukraine still lives in fear, despite escaping her ordeal as a prostitute.
Her tale of modern slavery is typical of those forced to work off enormous travel debts - the costs of being smuggled into western Europe.
"Ivana" ended up as a prostitute in Birmingham
Enslaved by the smuggling gangs "they are deprived of their freedom, abused, beaten, raped - they are clearly exploited," says Helga Conrad of the Organisation for Security and Co-operation in Europe (OSCE). The OSCE is co-ordinating action to combat the gangs.
Ivana - not her real name - told BBC World Service's Slavery Today programme how she left her home in Ukraine when promised job abroad as a waitress.
In her early 20s, she was trafficked to work as a prostitute in Birmingham, central England.
Police in the UK have discovered growing numbers of trafficked women in the country's brothels.
Ivana was kidnapped by a gang of people-traffickers and smuggled around Europe for six months.
"Then three huge men came into the room and threatened me. They demanded to see my body. They made me lift up my top and show them my breasts," she said, recalling the night she was taken.
"There was nothing I could do to fight them."
Following her kidnap, she was smuggled into Macedonia. When she got to Greece, she was sold to an Albanian man, who took her to the UK via Italy.
"The first time he raped me, I fought him off for half an hour - but he was a massive man, and I am quite small," she recalled.
"He was really crazy. He beat me all the time - even out in the street - with his hands, his feet, his belt. My body was just black.
"He used to make me work every day - even when I had my period. I used to see six, seven or even more customers a day. And I never saw any money from the work - he sometimes didn't even give me food."
'The dream has gone'
Only after a cleaner at the brothel saw her bruises following a particularly savage beating did she escape.
"I thought about killing myself by throwing myself out of the window of the brothel. But the cleaner saw how sad I was, and with the help of two other prostitutes, carried me into her car.
"I was so scared, because I knew if my pimp caught me, he would definitely kill me.
"When I left my country I thought I would be able to make money and buy a flat back home for my son and for me.
Many people are smuggled out of eastern Europe
"Now this has happened to me, that dream has gone. Everything has gone."
Ivana says she lives in fear her pimp will find her again.
If he does, she believes he will murder her.
Ms Conrad of the OSCE says that sometimes women "will accept and know that they're going to work in prostitution".
"But what then occurs to them, and how they have to perform and how they are treated, is something that they wouldn't have expected before."
One former trafficker, now working with the authorities and living at a secret address, told Slavery Today how his former gang would operate.
"Most of the time we would use professional recruiters, but at times we would kidnap women and children ourselves," he said.
"The children were taken to be sold in Italy, and the better-looking women were kept as prisoners and made to work as prostitutes.
"The men were transported wherever they wanted to go."
He also said that the youngest child who had been abducted was around 18 months old.
"I have heard that sick children are sold and made into beggars.
"The healthy ones are kept and trained to work for the Mafia, to deal drugs, to murder - whatever they are capable of.
"I've also heard that some children were sold for organs. This also happened with men and women, depending on the demand."
Some trafficked people have their organs removed
And he admitted to often using force to capture people.
"If they didn't want to be separated from their families, we'd hit them until they did what we wanted," he said.
"Generally threats are made that another family member will be murdered if orders are not obeyed."
Working in Eastern Europe, the gang would drive trafficked men into Slovenia, from where they would be transported, to look for work on places such as building sites.
Others were transported from Bosnia to Croatia by boat, across the river Sava - which was controlled by the gang.
From there, they would be taken north to the Hungarian border, where they would be smuggled through a forest.
The former trafficker, currently preparing to give evidence, also claimed that he knew of highly-placed officials who had been bribed by the smuggling gangs.
This was seemingly confirmed by Munir Podomlak, the leader of Croatia's Partnership For Social Development - an anti-corruption campaign that is sheltering the former trafficker.
Mr Podomlak said the man had revealed information covering trafficking in five countries, and accused diplomats and policemen "one way or another involved in crimes."
He insisted that authorities had "not really" been eager to help. He could only say that of the five countries involved, two were being more thoroughly looked at - one is in western Europe, and one in eastern Europe.
"They are probably going to do arrest in the coming months based on this case," he said.
"Our first impression, from talking to law enforcement agents in those two countries, is that they're also a little bit nervous about the level of this case - how senior the people involved are.
"Something much bigger is behind it, which we have no knowledge of."