A "gentleman's agreement" that allowed vulnerable children who entered the UK alone to be sent back to France has been ended after investigations by the Office of the Children's Commissioner (OCC).
The Landing in Dover report found the agreement allowed unaccompanied children to be sent back to France within 24 hours if they did not immediately ask for asylum.
The agreement was at odds with the UK Border Agency's (UKBA) duty to safeguard children and promote their welfare and has been ended after it was brought to the attention of UKBA chief executive Rob Whiteman, Children's Commissioner Maggie Atkinson said.
Just over 1,700 unaccompanied children who entered the country in 2010 sought asylum, whilst a number of those returned to France under the UK/France deal may have been trafficked for exploitation, the OCC found.
It found children seeking asylum include those escaping war zones and persecution, and they are often hungry, ill, exhausted and distressed when they arrive, so much so that they are unfit to be interviewed by officials.
The report also uncovered excessive periods of detention before release into local authority care, due to the number and length of immigration interviews at the point of arrival.
Dr Atkinson said: "Children arriving unaccompanied in the UK are some of the most vulnerable that my office and society encounters. That is why we have continued to investigate how they are dealt with, working constructively with UKBA, to improve their treatment.
"This has been advanced through the end of the 'gentleman's agreement'. I commend Rob Whiteman for acting decisively."
The Refugee Council described the report's findings as "shocking" and urged the Government to heed the recommendations to improve the screening system for children when they arrive, not just in Dover but in ports across the UK.
Donna Covey, chief executive of the Refugee Council, said: "We are very relieved that as a result of this welcome report, the disgraceful 'gentlemen's agreement' that has long put the wellbeing and safety of children at risk of harm and exploitation has now been put to an end. The report has shone a light on the lengths our Government is prepared to take in order to pass the responsibility for children arriving here back to other countries."