Hundreds of child refugees are missing in the UK, The Independent can reveal, amid fears they have fallen victim to human traffickers or other forms of exploitation such as sexual abuse or modern slavery.

Authorities have no idea of the whereabouts of 360 of the vulnerable children, or even if they are safe. More than 200 have been missing for over two years, prompting serious concerns for their safety.

Campaigners and MPs say the figures, released to The Independent by the Home Office under freedom of information rules, show the children have been “failed” by Theresa May’s government and are “being let down by a system which is meant to keep them safe”.

Over the past five years, 9,287 children have sought safety in the UK as “unaccompanied minor” asylum seekers travelling alone, without a parent or guardian. Many of the children are fleeing war, poverty and persecution in their home countries. During this period, 360 have gone missing and are still unaccounted for. Of these, 81 of the children have been missing for five years, a further 77 children have been missing for four years and another 87 children have been missing for three.

When an unaccompanied child asylum seeker arrives in the UK, immigration or border staff have a duty to inform the local authority who is responsible for the child’s welfare. After an assessment by duty social workers, some children are placed in children’s homes, while others are placed with foster families. After this, social workers are required to regularly check up on the children through routine meetings or phone calls to ensure they are safe and remain in their children’s home or with their foster family.

Authorities, including the Home Office, are alerted when social workers are unable to contact child refugees, for instance if they do not answer phone calls, fail to attend scheduled meetings or if a children’s home reports they have disappeared from the care arrangement.

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Child refugees may disappear for many reasons, including falling prey to traffickers, running away due to trauma or distress, serious mistrust of authorities or fear of deportation.

The figures were released a year after the death of Alan Kurdi, the three-year-old boy who drowned in the Mediterranean sea while his family were trying to flee Syria. Following a campaign by The Independent in the aftermath of Alan’s death, then Prime Minister David Cameron announced Britain would do more to accept refugees.

However, it was revealed earlier this year that fewer than 20 children had been granted asylum in the first three months of 2016. Campaigners and politicians now say these new figures on the number of missing child refugees shows that of the few who are granted asylum, the UK is failing to provide adequate support to ensure their safety once they arrive.

Research by the EU’s criminal intelligence agency Europol earlier this year found 10,000 child refugees have gone missing across Europe since registering with state authorities. 5,000 children are missing in Italy, while a further 1,000 are missing in Sweden.

The Children’s Commissioner for England, Anne Longfield, told The Independent that the Government must act to trace those missing in the UK. She said: “Any child who goes missing can be exposed to people who seek to harm them, so there is certainly no room for complacency when it comes to tracing them.

“Authorities must carry out proper risk assessments and put in place safeguarding plans for all children who are in their care and there needs to be clear communication about responsibilities when they move between areas. They must also work with the police to ensure that any child who goes missing child is located as soon as possible so that they can be protected.”

Labour MP and former shadow home secretary Yvette Cooper said the figures show children are being “let down” by a system “turning a blind eye” to their vulnerability. She said: “We are failing victims of child trafficking, effectively turning a blind eye to their disappearance. They are being let down by a system which is meant to keep them safe.

“For years, the government has been warned about vulnerable children, often victims of the most heinous crime of child trafficking, disappearing from the system. As Shadow Home Secretary, I called on Theresa May to implement a nationwide system of legal guardians to monitor child victims of trafficking living in the UK, as part of the Slavery Bill. The government’s trial ended last September, so why do we still have no concrete policy change to protect these children?

“If the now Prime Minister is serious about addressing modern slavery, she would urgently address this crisis.”

The other Alan Kurdis: Refugee children who survived the journey Show all 8 1 /8 The other Alan Kurdis: Refugee children who survived the journey The other Alan Kurdis: Refugee children who survived the journey Basheer Basheer, a 3-year-old Syrian boy, lying on his father leg, lives with his family in a rent-free house as part of NRC's shelter programme in the village of Bair-Ras, in Irbid governorate, northern Jordan. Photo 11 October 2015 NRC/Hussein Amri The other Alan Kurdis: Refugee children who survived the journey Hisham Mustafa has fled from Aleppo, and is currently at Idomeni in Greece. Here he is playing with his nephew Hisham, 3 NRC/Tiril Skarstein The other Alan Kurdis: Refugee children who survived the journey Ahmaydi Bouchra Little Ahmaydi, 3, and her family of eight fled from fighting in Mali to the Goudebo camp in Burkina Faso in 2013. Neither of her two older sisters went to school in Mali. The whole family lives in a tent that is approx. 7m x 6m. The family bed is stored outside to make space inside the shelter during day time. In the evenings, they carry the bed back in. NRC/Ingrid Prestetun The other Alan Kurdis: Refugee children who survived the journey Farah Farah, 4, lives with her family in Irbid in a rent-free apartment. She stays home with her mother as her four sisters and three brothers leave for the day to their various schools. Photo 11t October 2015 NRC/Hussein Amri The other Alan Kurdis: Refugee children who survived the journey Batane Yacouba Batane Yacouba, 4, lives with his two older sisters and his mother in the Goudebo camp in Burkina Faso. A Tuareg family, they were forced to flee Mali fearing for their lives. Their father is dead NRC/Ingrid Prestetun The other Alan Kurdis: Refugee children who survived the journey Hassan Syrian boy Redor, 12, plays with Hassan, 3, after arriving at the port in Chios, Greece NRC/Tiril Skarstein The other Alan Kurdis: Refugee children who survived the journey Fatin Fatin, 4, and her family fled Syria to Irbid, northern Jordan. Her father has issued a birth certificate for her, in order for her to have access to health centres. NRC/Hussein Amri The other Alan Kurdis: Refugee children who survived the journey Born a refugee Alice Digama (24) sits on the tent floor with her two-week-old baby. Her son is one of many children born a refugee. Alice was heavily pregnant when she escaped South Sudan and crossed the border into Uganda, after her husband left her for another wife NRC/Sofi Lundin

Leader of the Liberal Democrats Tim Farron said the numbers were "absolutely disgraceful" He added: "Unaccompanied refugee children are some of the most vulnerable in our society and it is likely that many of these missing children will now be in the hands of traffickers and gangs.

“The government must urgently review its processes to ensure that children can’t simply vanish from care."

Child welfare experts have warned missing children refugees are extremely vulnerable and often suffering from severe trauma, while lacking any family or support networks to turn to. It is feared trafficking gangs may therefore prey on them.

Frances Trevena, of Coram Children’s Legal Centre Migrant Children’s Project, said: "Trafficking gangs run sophisticated networks in order to traffic children into or within the UK for the purposes of exploitation, including sexual exploitation, forced labour and domestic servitude. Those who do go missing are at a great risk of exploitation from their traffickers or others who may seek to exploit them further.”

In response, a Government spokesperson said: “Vulnerable children must be kept safe – that is why when a child goes missing from care, agencies work closely with local authorities and local police forces to find them.