Of the 1.2 million refugees and migrants who applied for asylum in Europe in 2015, nearly 350,000 were children – many of them minors without their parents. Britain has said it will take in some unaccompanied refugee children from Syria, north Africa and other conflict areas, but did not say how many. This is in addition to the 20,000 Syrian refugees the government has pledged to take in by 2020.

Migrants and refugees have had to brave temperatures as low as minus 15 degrees Celsius (5F) to cross frozen Balkan borders en route to western Europe, visibly unprepared for winter and in increasing danger from the cold. Men, women and children covered in blankets have been forced to sleep rough in tents or next to bonfires in the open. Save the Children said that women, children and babies are in danger of contracting hypothermia.

Migrants have been arriving in Serbia with blue lips, distressed and shaking from the cold. Exhausted mothers have told the group's aid workers they are unable to keep their babies warm and dry, and that some have slipped while carrying them on icy roads. The United Nations and aid agencies have warned that children are at risk of freezing to death given their lack of adequate clothing or access to sufficient nutrition.

Many of the people making this arduous journey are fleeing conflict zones such as Syria, Iraq and Yemen, where millions of people are gripped by hunger, struggling to survive with little help from the outside world. Children suffer from severe malnutrition, their parents often having to beg or sell possessions to get basic commodities including water, medicine and fuel. According to the UN children's agency, malnutrition is a major threat for millions of refugees.