An 18-year-old student from Afghanistan told he could stay in the UK until he had completed his A-levels has now learnt he will have to leave next May.
Amin Buratee says he feels like he is being treated as a criminal
The decision to allow Amin Buratee, who lives in Whitstable, Kent, to study for his exams, came after he was held for 10 days in a detention centre in Dover.
He is due to sit his exams in 2006, but the Home Office now says he can only stay in the UK for six months.
A Home Office statement said it could not comment on individual cases.
Amin, whose father, uncle and brother were killed by the Taleban, is a pupil at Canterbury High School, and came to the UK two years ago after their deaths.
Classmates staged a protest in Canterbury last month after he was arrested in a dawn raid by immigration officials and taken to the Dover Removal Centre.
His case was taken up by local Tory MP Julian Brazier, who lobbied Home Secretary David Blunkett and immigration minister Des Browne to allow him to stay.
Speaking to BBC Radio Kent on Monday, Amin revealed that he had to regularly visit a police station to "sign on", and was being made to feel like a criminal.
"I feel really scared because every time I go to the police station I don't know what's going to happen - they'll probably change their mind and arrest me."
A statement from the Home Office said: "All asylum applications are considered individually by skilled case workers.
"The UK Government will grant asylum for those with a well-founded case of persecution under the Geneva Convention of 1951.
"If an application is refused, applicants have the right of appeal before an independent adjudicator.
"People are removed only after appeals have been heard and dismissed."
Whitstable councillor and supporter Wes McLaughlin said unfair pressure was being placed on the student.
He said he was hopeful that when clarification was sought from the Home Office, it would behave more reasonably and "in the spirit" of the original decision.