Aspiring mathematics student Yashika Bageerathi has been deported from the UK to her home country of Mauritius after a judge refused to grant her asylum.
Lawyers represeting Bageerathi had sought an injunction on her deportation to allow them time to take her case to the court of appeal.
But Lord Justice Richards refused the application and 19-year-old Bageerathi continued her journey to Heathrow Airport.
Immigration minister James Brokenshire said on Monday that the Home Office decided she did not need protection from violence or persecution in her homeland.
The deicison raised the ire of campaign groups who had fought for Bageerathi to stay in the country and finish her end-of-year A-level exams at Oasis Academy in Enfield, north London, which take place next month.
A petition calling on Home Secretary Theresa May to step in and stop the deportation gathered almost 180,000 signatures on the website Change.org.
It claimed the deportation would infringe Article 8 of the Human Rights Act, which enshrines a person's right to respect for private and family life.
Describing Bageerathi as a valuable member of society, the petition read: "We, the undersigned, refuse to accept that this is an appropriate, compassionate or logical course of action. We call upon the Rt. Hon Theresa May MP, Home Secretary, to overturn this ruling so that Yashika can - at the very least – complete her education in the UK.
"Since enrolling at Oasis Academy Hadley, Yashika has made an outstanding contribution to the life of the academy. Not only is she an incredibly talented mathematician, she has spent considerable time helping to train, teach and coach younger students in the subject, transforming their learning experience. On top of all of this she has poured herself into voluntary activities, helping the Academy to win a national award in recent months."
Bageerathi came to the UK with her mother, sister and brother in 2011 to escape a relative who was physically abusive.
The family claimed asylum last summer but faced the threat of deportation. The case of Bageerathi is being considered in isolation from the rest of her family because she is now an adult.
Two previous attempts to deport her were stopped when airlines reportedly refused to let her board their aircraft.
Dozens of students gathered at Oasis Academy at the weekend to protest for their peer to stay in the country but their calls, and those of the 180,000 signatories on the Change.org petition, went unaswered after Lord Justice Richards upheld the Home Office decision to deport Bageerathi.