Lone child asylum seekers and trafficked children are going missing at an "alarmingly high rate" from care in the UK, charities have warned.
More than 200 of around 760 such children who disappeared in the year leading up to September 2015 have still not been found, they said.
Charities ECPAT UK and Missing People found that 167 trafficked children in care, which is 28% of such children, went missing at least once.
And 13% of unaccompanied children, including refugees, in care (593 children) went missing, their study found.
"Of these, 207 missing trafficked or unaccompanied children had not been found," the report to be presented in Parliament on Wednesday said.
Chloe Setter, head of advocacy, policy and campaigns at ECPAT UK, branded the problem "a national disgrace".
She said: "For too long, children who are at risk of exploitation, or who have been trafficked, have gone missing from care - sometimes repeatedly, sometimes forever.
"It is a national disgrace that this problem has remained neglected and these children rendered invisible by poor data collection and national co-ordination."
The report, titled Heading Back to Harm, called for carers to build a "culture of trust" with children to stop them disappearing in the first place.
The charities also called for greater training for professionals and carers as well as improved data recording to detect patterns of children going missing from care.
British, Vietnamese and Albanian children are the top three nationalities of missing trafficked children, according to the research.
The charities compiled data from 217 local authorities who responded to requests under the Freedom of Information Act.
Susannah Drury, director of policy and research at Missing People, said trafficked and unaccompanied children are "especially vulnerable".
She said: "It is therefore vital that any trafficked or unaccompanied child who goes missing is treated as high risk by the police and other agencies and that finding them and making them safe is always prioritised over any questions about their immigration status or criminal activity."
A Department for Education spokesman said the children's exceptional vulnerability was recognised.
He said: "That's why we have commissioned specialist training for those caring for them, committed to an independent advocate in each area to help champion their rights and outlined clear plans for a new Government strategy to look at their particular needs, including reviewing the accommodation available."