A Home Office investigation has found that an adult asylum seeker posed as a schoolboy and was placed in a classroom of 15-year-olds.A new inquiry has been launched to try to establish how the man, described by pupils as looking 30 years old, managed to spend six weeks as a Year 11 pupil at Stoke High School in Ipswich, Suffolk.The former pupil, originally from the Middle East, now faces being deported after the official report established he was over 18.The man, known as Siavash, can now be identified for the first time. He was first pictured on social media by a fellow pupil with the message: “How’s there a 30-year-old man in our maths class?”Other pictures apparently from the man’s Facebook account showed him with a moustache, facial stubble and drinking from a bottle of beer.Some parents were so concerned that they removed their children from school. The scandal prompted the school to remove the man, believed to be 6ft 1ins tall. Stoke High School in Ipswich, SuffolkCredit:Harry Hubbard/SWNS “The threshold is set deliberately high so that only those who are very clearly over 18 are assessed as adults.” A department spokesman said: “We are fully committed to safeguarding children and are looking into the circumstances of this case to understand how it was handled.“Age-disputed cases remain a challenging area of work in which no single assessment technique, or combination of techniques, is likely to determine an individual’s age with precision.”In the absence of clear and credible documentary evidence, Home Office staff must rely on physical appearance and demeanour to make an initial assessment on whether a person claiming to be a child is under 18.”If an individual is assessed to be under 18, but subsequent concerns about their age are raised – for example by a school – we will act quickly to reconsider the case.”A spokesman for the school, run by the Ormiston Academies Trust, confirmed the Year 11 pupil is no longer there, adding: “This is a matter for the Home Office. We cannot comment further on individual cases.”A Facebook profile apparently by the man described him as having been an architecture student at the Islamic Azad University in Abadan, Iran, before living in Erfurt, Germany. The account has since been deleted.Rumours had been rife in Ipswich that the man was even married and had children. Although the Home Office refused to reveal what age he is now believed to be, it is understood from sources that he is being treated officially as an adult asylum seeker. Asylum seekers believed to be under 18 who arrive in Britain are entitled to a state education. However, if concerns are then raised that they may be older than initially thought, the school can report them to the Home Office, which then instruct social workers to make an assessment of their true age.However, they are only assessed as adults if there is “clear and credible documentary evidence” or if two immigration officers rule that their “physical appearance or demeanour very strongly suggests they are significantly over 18 years of age”.The Home Office spokesman added: “When there is doubt about an individual’s claim to be a child, the individual will be referred to a local authority’s social services department for a careful, case law-compliant age assessment and they will be treated as a child until a decision on their age is made.”If an individual is assessed to be over 18, we will process any asylum claim as being made by an adult. If the application is unsuccessful, and appeal rights are exhausted, removal action will be pursued as appropriate.”In the absence of documentary evidence, Home Office staff are only able to treat a claimant as an adult if their physical appearance and demeanour very strongly suggest that they are significantly over 18 years of age – and where two officers have reached this conclusion independently. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.