Women who have been trafficked into the country to work as prostitutes, drug mules or domestic servants can end up in UK prisons without any protection or support, while traffickers walk free, new research has found.
Many of the vulnerable women get none of the protection from UK authorities that they are entitled to under international law, with a police investigation into the traffickers launched in just one out of 40 cases.
Responding to the University of Cambridge study into trafficking, Prison Reform Trust director Juliet Lyon, said: "It is shameful that terrified women who have been repeatedly raped and abused could find no one at police stations, courts or jails that they could trust or turn to for help."
There were 58 foreign women in prison or detention centres whose crimes are directly linked to what they were forced to do by traffickers, the report by Professor Loraine Gelsthorpe and Dr Liz Hales found. Forty-three were identified as victims of human trafficking, and five more who had entered the country independently had worked under "slavery like conditions."
Nearly half - 20 - were forced to work in prostitution and 15 had been made to work in producing cannabis.
Eight had been forced into domestic service, two had travelled as drug mules and eight were involved in street robberies and the sale of fake goods.
Five of the women had been trafficked to the UK as children - and one had been trafficked from her home country twice, coming to the UK after she was deported from the first country her traffickers sent her to.
Of the trafficked women in prison, 24 women said they had experienced multiple rapes. For two of the women this was an on-going threat.
And some women asked prison doctors for help with severe abdominal pains, heavy bleeding and discharge following extensive rape and sexual abuse.
Prof Gelsthorpe, at Cambridge's Institute of Criminology, said: "There should be renewed efforts to recognise that 'offenders' can also be 'victims', and to ensure that appropriate credence is given to women's accounts of their own experience.
"This is important research in terms of access to justice. The message is clear - the powerlessness of these women in the hands of their traffickers is terrifyingly replicated within the criminal justice system.
"Yet the legitimacy of the criminal justice system stands or falls on the way in which we treat victims as well as offenders."
There were 616 foreign national women in prison, as at the end of September, accounting for one in seven of the total female prison population.
Guidelines were introduced in 2009, the National Referral Mechanism, to identify victims of human trafficking and ensure they receive appropriate protection and support.
But just 11 women had been dealt with according to NRM advice.
The report's findings will be debated on Wednesday by MPs and peers at a seminar in the House of Lords convened by the Prison Reform Trust.
Parliamentarians will consider recommendations for a national strategy on foreign national women in prison and better monitoring of the UK's obligations under international law.
The UK Human Trafficking Centre, run by the Serious Organised Crime Agency, which works with first responders like police to implement the NRM, told HuffPost UK that they believe the guidelines are being successfully implemented, but it was up to individual forces to decide whether to use the guidelines when dealing with victims.
A Government spokesperson said: "We are working harder to identify victims of trafficking earlier.
"We are doing this by raising awareness of how to identify victims, providing expert training to law enforcement officers and providing £2 million a year to help and support victims, including those identified in either the Prison or Probation service.
"We try not to detain victims of trafficking. People who have been trafficked can find it very hard to talk about what has happened to them, which means that sometimes they may be detained for a short period before they are identified as victims.
"We must ensure they get every possible support, and that offenders of this sickening crime are brought to justice."