Young people from Syria and Libya told the charity they suffer a range of abuses at camps in Dunkirk and Calais, including being coerced into performing sex acts on traffickers and forced to commit crimes, The Independent reported on Monday.
The research takes the form of a series of interviews conducted over the course of six months and will be published in full on Thursday.
Bilal (not his real name) a 16-year-old boy from Daraa, Syria, was stuck in a camp without his family for seven months and told UNICEF about the conditions he and his brother were held in.
“The worst part of my journey was being in Calais because most people there were subjected to violence and humiliation,” he said.
“Every day people would try to find ways of leaving. My friends and I tried to get on a train to get away – I saw two friends die under that train.”
The charity reports there are at least 157 unaccompanied children living in the Calais Jungle camp who are waiting to be reunited with their families in the UK.
Lliana Bird, co-founder of the charity Help Refugees, said from Calais, “We do get these kinds of reports from refugee children fairly often, which is extremely worrying.
“We hear all sorts of horror stories about how they are treated in the camps, many of which are too horrific to even detail.
“It all goes to reinforce the point we are making – unaccompanied minors are the most vulnerable people in Europe right now, and it's up to the government to put proper registration systems in place to give children safeguards against this kind of exploitation.”
In April, Help Refugees revealed 129 unaccompanied minors had gone missing from the Calais Jungle shortly after the site was demolished, and more than 10,000 over the past two years across Europe.
There are around 4,946 at the Calais refugee camp, around 500 of whom are children.