Ministers were warned three years ago of age-check problems
August and the Home Office didn’t take it up at the time.
“They only started asking for social workers with age assessment experience on Friday.”
It has also emerged that ministers were warned three years ago that adults were posing as child refugees by John Vine, then the Independent Chief Inspector of Borders and Immigration
In a June 2013 report he said officials at Dover had warned that “many of those claiming to be minors were men whom any observer would adjudge to be in their mi-twenties, or older”.
Mr Vine added that the speed with which a child’s asylum application is approved had “created an incentive for adults to claim to be under 18”.
Britain has made a number of commitments to help child refugees after a surge in migration into Europe from the Middle East and Africa, partly as a result of the Syrian civil war.
Some 3,000 children are being taken in from camps in the Middle East, while some who have made it as far as mainland Europe are also being resettled in Britain if they have close family links.
David Cameron also agreed in May to take in more unaccompanied child refugees from continental Europe after political pressure from Lord Alf Dubs, the Labour peer.
However, The Sunday Telegraph has learnt that there were major concerns in the Home Office, Theresa May’s department at the time, about whether that last promise could be delivered.
A Whitehall source familiar with the discussions said Mrs May was worried about how the decision would be implemented and feared it would encourage more migrants to move to Calais.
“There were warnings that it was impossible to organise in an efficient way, including age verification and where they came from,” the source said.
“Theresa was very concerned – as we all were – that if we conceded to Alf Dubs there would be thousands more heading to Calais.”
This week fresh conflict is expected in Calais as some 1,250 police and gendarmes will oversee an operation to clear and then demolish the “Jungle” camp. The 6,500 migrants there will be sent to 450 reception centres across France.
Mrs May is expected to come under fresh pressure over her handling of age checks of child refugees in Parliament on Tuesday.
Two MPs on the Commons home affairs committee have told The Sunday
Telegraph they will demand an “urgent” inquiry into the affair.
Tim Loughton, the Tory MP and interim chair of the committee, said: “There is a role for the committee to have an urgent short inquiry into what is going on to help restore confidence that we are doing the right thing by the right people in the asylum system.”
David Burrowes, the Tory MP for Enfield Southgate, said he wanted the focus to be on whether Britain is meeting its “legal duty” to help child refugees.
A Home Office spokesman said: “We are working closely with the Local Government Association, NGOs and across government to make sure we bring all eligible children to the UK as soon as possible.”