Those in Italy, one of the main gateways, were mainly unaccompanied, boys, aged 16 -17 who had decided for themselves to attempt the hazardous crossing.

By contrast, in Greece – the other main entry point – 91% were with family members who had taken a joint decision to emigrate.

For those who travelled, mainly across Africa, the systematic trauma and abuse they witnessed or suffered in Libya caused them to flee to Europe, Unicef research showed.

Some 75% of refugee and migrant children interviewed in Italy decided to make the journey alone, some due to violence at home, deprivation, conflict or child marriage.

Unicef’s regional director for Europe and Central Asia Afshan Khan said: “What is striking about this study is it shows for the first time that there are overwhelmingly far more reasons that push children to leave their homes, than has been previously understood, and fewer pull factors that lure them to Europe.

“For those who did aim to come to the continent, the allure of Europe was the chance of furthering their education, respect for their rights and getting ahead in life. However once they reach Europe the reality is sadly quite different and their expectations are shattered.”

Interviewees in Italy unanimously reported their time in Libya as the most traumatising part of their journey on land, with 47% having been kidnapped for ransom and 23% arbitrarily arrested and jailed.

Sol Oyuela, director of public affairs at Unicef UK, said: “Tens of thousands of life threatening journeys at sea could have been avoided. Children aren’t leaving their homes out of choice – they’re fleeing war, persecution and poverty.”

Oyuela said the UK government should allow children to reunite with siblings, grandparents and other relations, as the absence of workable family reunion rules meant “children will continue to risk drowning at sea and being forced into the hands of traffickers and smugglers”.