More than 150 children with close family in Britain are living alone in a Calais refugee camp, new research shows.
A report by aid charity Citizens UK found there were 157 unaccompanied children in the border camp known as the Jungle who have close family members in Britain to live with.
Four leading charities have now called for the Government to take urgent action following the report.
Citizens UK, Save the Children, Unicef UK and Help Refugees want the Government to address the number of unaccompanied refugee children in Europe, ahead of a parliamentary debate on the topic, as part of the Immigration Bill on Monday.
Of 157 children in Calais with family links to the UK, two are just ten years old. The charities say the children are traumatised by war, living rough, and facing a long and complex bureaucratic procedure before being reunited with their families in Britain.
Neil Jameson, of Citizens UK, said the Government needed to speed-up the process for these individuals, and added: "The fact that children, who have a legal right to come to the UK, are living alone in tents in Calais is a national embarrassment."
According to Help Refugees, there are currently 4,946 refugees in the camp. Josie Naughton, co-founder, referred to the UK's Kindertransport scheme which rescued thousands of Jewish children from Nazi Germany.
She said: "There are hundreds of unaccompanied children in Calais, and thousands across Europe, scared, alone and extremely vulnerable. According to Europol, 10,000 refugee children are missing in Europe. This is the same number of children that the Kindertransport rescued from Nazi persecution. We hope our government remains on the right side of history."
Last year, approximately 95,000 refugee and migrant children travelled to Europe alone, or lost their families in transit. Save the Children said there were more than 2,000 lone child refugees in Greece trapped after the closure of the Balkans route. They said the Greek system was overwhelmed and safe shelters were oversubscribed.
The charity also highlighted the problem in Italy where, in a period of 48 hours last week, more than 450 children arrived alone.
Tanya Steele, chief executive of Save the Children, said children in Europe, who have fled wars on their own, needed protection.
She added: "We should be speeding up family reunification so that children with relatives in the UK can live in safety with them, but must also reach out a hand to those vulnerable children who have arrived in Europe and have no family to join."
Unicef suggested the EU-Turkey deal on migrants, and border closures, could be making the situation worse. The group said it could increase the risk of abuse of unaccompanied children, psychological trauma and exploitation by traffickers and criminal gangs, amid the chaos.
The children's charity also added that the new agreement could push people into taking more dangerous routes.
Lily Caprani, of Unicef UK, said: "It is simply an injustice that the life of any child, anywhere, has been put on hold for all this time - these children in Calais have families waiting for them here in the UK. They cannot be left like this, in this state of limbo."
The charities say the Government must do all it can for those children who have a legal right to be with their families in the UK.