A/HRC/15/29 with appropriate training and support to carry out their functions effectively.31 Under no circumstance should unaccompanied and separated children be refused entry to the territory. B. Border controls 39. The border can be a dangerous place for migrant children, including separated and unaccompanied children. They can be subject to high levels of violence by border guards and arbitrary and prolonged detention, and can be denied the right to seek asylum. Children at borders are often regarded with suspicion by officials who cast doubt on their age and motivations for movement. 40. Interception practices at land, sea and air borders can be arbitrary and even unlawful, with entire groups of migrants, including unaccompanied and separated children, being pushed back to transit countries or countries of origin. The humanitarian needs of migrants in such circumstances, some of whom have been on the move for weeks or months, are ignored. Because of their heightened vulnerability, children will often suffer disproportionately. Equally seriously, protection needs can also be ignored, often with drastic consequences. 41. International law provides an absolute prohibition of refoulement, i.e., the return of anyone to a country where they would be at risk of torture, cruel, inhuman and degrading treatment,32 or the return of a refugee to any country in any manner whatsoever where his or her life or freedom would be threatened.33 All children should have access to an effective procedure to establish, in a child-friendly manner, the risk they would face if returned to their country of origin, or to any risk of “chain refoulement” (i.e. removal to third countries in which the person would be at risk of refoulement). This would include access to asylum procedures and procedures to establish whether they have been subject to trafficking and other serious human rights violations. Where appropriate, border authorities should promptly refer migrant children to child protection authorities and other relevant services. An independent guardian or legal advisor should be appointed promptly to advise and protect separated children.34 C. Age assessment 42. Despite the fact that the assessment of age can be the key to being protected as a child, many migrant and asylum-seeking children can be subject to inappropriate age determination techniques, which can interfere with their right to privacy and violations of their human dignity. The false belief that such techniques are an exact science can lead to serious errors35 and can place children at risk of refoulement, detention and denial of essential services.36 31 32 33 34 35 European Union Agency for Fundamental Rights, “Separated, asylum-seeking children in European Union Member States”, summary report (April 2010), p. 34. Convention against Torture, art. 3. Convention relating to the Status of Refugees, art. 33. SCEP, p. 16. Medical assessment methods, such as bone and teeth analysis, are associated with a margin of error of at least two years in either direction. This can be compounded by cultural differences in recording age, and lack of documentary evidence. One report has noted that in some countries an official “culture of disbelief” pervades the issue of age assessment, putting the burden of proof on the child to prove that they are not adults. See Heaven Crawley, “When is a Child Not a Child? Asylum, Age 11