Orphaned at 10, Grace was begging for food and living on the streets of Lagos, Nigeria until she met a woman who promised her a job and a better life in England. The woman was true to her word and brought Grace to Britain - to work as a prostitute. For three months, Grace was beaten, forced to have sex without condoms and barred from going outside before escaping her traffickers. But even then her troubles were not over. Advised to seek asylum in Britain, Grace was seven months pregnant when she was sent to a detention centre after her asylum claim was rejected. Although released shortly before giving birth, Grace was sent to yet another detention centre six months later while her appeal was being processed - this time with her baby daughter. She was eventually recognised as having been trafficked and allowed to stay. Leading London-based women\'s charity, Eaves, says Grace should never have been detained. The group, which runs a project helping trafficked women, is behind an e-petition calling on Britain\'s government to stop detaining trafficked people. The petition needs at least 100,000 signatures to force MPs to debate the matter in parliament. Eaves says cases like Grace\'s contravene the Council of Europe Convention on Action against Trafficking in Human Beings - a treaty signed and ratified by Britain, which states among other things that people who are trafficked should not be held in detention. Part of the problem is getting the authorities to identify trafficked women in the first place, Eaves\' research and development manager Heather Harvey said. It is often the UK Border Agency that determines whether an individual is trafficked, the same agency that is in charge of deporting illegal immigrants - raising concerns about how effectively the UKBA can carry out its dual role, Harvey said. \"If your role is to deport illegal immigrants then it\'s not necessarily in your interests to facilitate and enable somebody to make a really good case for why they would stay here,\" Harvey told TrustLaw. \"If you\'re not recognised as a victim of trafficking, you\'re likely to end up in detention, in prison, be deported …\" she added. Eaves takes on about 40 percent of the cases which are referred to it, a quarter of which come from prisons or detention centres where many trafficked women are kept for immigration offences. Stacy Ziebell, Eaves\' support worker at detention centres and prisons, said many detained women have tried to flee their traffickers or the United Kingdom using false documents. Some women are working with false documents given to them by their traffickers. She described visiting trafficked women in prisons and detention centres and witnessing how rapidly their mental health deteriorated in many cases under the pressure of detention. \"Some of the women I\'m seeing are pregnant, are minors, some of them are pregnant minors, some of them are victims of torture as well as victims of trafficking,\" Ziebell said. \"So it\'s not just that they are victims of trafficking and are in detention - although that should be enough within itself - but there are also added factors.\"