They are lured into Northern Ireland under the pretence of embarking on a new life.

Conned by fake newspaper advertisements for jobs as nannies or domestic workers, vulnerable women from China, Malaysia, Zimbabwe, Ethiopia, Romania and Slovakia are unwittingly thrust into the murky underworld of Ulster’s sex trade.

Threatened and beaten, some victims are also drugged and raped. All have their passports taken from them.

The women are told they have a debt to pay off and are forced into prostitution, made to have sex with up to 10 or 15 different men a day.

Many are so disorientated they don’t even know which country they are in and are too frightened to attempt escape.

“You have got to bear in mind these people are very, very frightened,” explained Detective Superintendent Essie Adair from the PSNI’s Organised Crime Branch.

“They have been threatened, their families have been threatened and, I suppose, they don’t know Northern Ireland and in some circumstances they don’t even know they are in Northern Ireland.

“They don’t know who to trust. They don’t necessarily trust the police because of their dealings with the police in China. When they are rescued they range from being quite calm about it to being absolutely, horrendously scarred.”

Victims are frequently moved from house to house so as not to arouse suspicion and prevent any chance of escape.

“Some are brought into the UK and then flown over to Northern Ireland. Some are victims who have been put into the back of lorries who were brought over from Europe. You also have the land border as well,” said Det Supt Adair.

“Once we identify there is a victim of trafficking in certain premises we will take action because the whole issue around trafficking is that it’s victim centred. The victim must come first.

Det Supt Adair added: “Many of our victims have said they don’t want to get involved with the police investigation, that they don’t want to go to court. They just want to get repatriated back to their own country.

“Once a victim says that, there’s nothing we can do. We can’t force them to work with us and give evidence.”