A Carmarthen A-level student who is facing deportation to Pakistan has admitted lying about who he really is and his parents' death.
There has been a high-profile campaign backing Ahmer Rana's fight to remain in Wales since before Christmas.
But he has revealed he is Daniyal Shahzad, who is 19 and not 18, and that he came to the UK to earn money to send back to his family in Pakistan.
The UK Border Agency said a judge found "inconsistencies" in Mr Rana's case.
Mr Shahzad has lived in Wales since 2008, when he moved in with foster parents John and Lesley Hillard in Nantycaws, Carmarthen.
But he was told that once he turned 18, as he claimed last Christmas Day, he would have no right to remain in the UK.
His earlier claims that he had no family in Pakistan and feared his missing parents were dead won huge public sympathy.
Two days before Christmas his supporters travelled to London to present a 4,000 signature petition against deportation to the Home Office.
Now Mr Shahzad, a student at Queen Elizabeth High School, has admitted that the story began with one small lie to the Home Office and snowballed out of control.
He told the Swansea Evening Post the true reason he came to the UK was to earn money to send back to his family.
"I would like to say sorry to my friends in school who have supported me," he told the paper.
"I have let everyone down."
His foster parents are said to be shocked at the revelations.
Jonathan Edwards, MP for Carmarthen East and Dinefwr, had earlier given his backing to Mr Shazhad.
He said: "This is a tragic story which shows that Ahmer is obviously a very vulnerable young man. These new revelations indicate how troubled his past has been.
The MP said Mr Shahzad's fight to remain in the UK was still valid.
He added: "Ahmer has clearly integrated into the local community, building and developing strong links which are clearly indicated by the strength of the campaign against his deportation.
"It would of course have been better for Ahmer to have been truthful from the start, but clearly he has been under tremendous pressure to provide for his family from an extremely young age which has undoubtedly put him in the position he is in."
A UK Border Agency spokesman said: "The UK Border Agency has fully considered Mr Rana's case and in an appeal hearing where his evidence was tested, a judge upheld our decision that he does not need the UK's protection.
"The judge found elements of Mr Rana's case were inconsistent and that he failed to show that he faces persecution in Pakistan. A further legal challenge has also been dismissed by the courts.
"Individuals like Mr Rana should leave the UK voluntarily when they have no legal basis to remain here, but if people defy the decisions of the courts we are left with no choice but to enforce their removal."
He added that Mr Rana's legal representatives are appealing against the judge's decision.
Nothing will happen to him until that appeal is heard.