Over 50,000 unaccompanied child refugees have gone missing from asylum seekers centres across Europe over the last three years, 850 of whom disappeared while in the care of the Dutch authorities, an investigation by journalism collective Lost in Europe has shown.

In the Netherlands, some 15,404 unaccompanied minors were registered in the last three years. Of them, 850 disappeared without trace.

Last year alone, at least 360 teenagers went missing from the Ter Apel refugee reception centre. While some may have joined relatives elsewhere in Europe, others are feared to have ended up in the hands of criminals or the sex trade.

Most of the missing youngsters are between 12 and 18 but some are even younger, the investigation showed.

The European figure is double that of the three preceding years when some 18,292 youngsters went missing. “The real number is likely to be much higher,” Lost in Europe journalist Geesje van Haren told broadcaster Nos.

Of the 31 European countries approached for figures, just 16 complied. Greece, Spain and France did not provide any data. “Those are countries with huge migration streams,” Van Haren said.

Plans for a European central registration of minors using their fingerprints is a good development, Van Haren said. “Although we have heard stories of teenagers who were forced to file down their fingertips by criminal organisations,” she said.

Dutch human trafficking rapporteur Conny Rijken said some of the children who vanished in the Netherlands end up being exploited in the cannabis industry, nail bars and in prostitution.

“We should stop moving them around and give them a permanent place to live, where they can be better protected,” she said.

Children’s ombudsman Margrite Kalverboer said it was typical that no amber alert has ever been issued for any of the missing children.

“They are regarded as aliens (..). But these children have fled their country without their parents and we are doing nothing to protect them. We don’t look for them. We don’t help them find their parents. We are not offering them the physical and educational safety they need,” she told the NRC.

According to article 22 of the the UN convention on the Rights of the Child, that is what the government should be providing, she said. “A child that is cared for is less likely to disappear,” she said.