A woman stripped of her British citizenship after leaving the country as a teenager to marry an Islamic State group fighter lost her appeal against the decision on Friday.
London's Court of Appeal rejected all five arguments presented by Shamima Begum, 24, although she can still take the case to the supreme court.
"It could be argued that the decision in Miss Begum's case was harsh, it could also be argued that Miss Begum is the author of her own misfortune," said judge Sue Carr as she delivered the decision.
"But it is not for this court to agree or disagree with either point of view, our only task is to assess whether the deprivation decision was unlawful. We have concluded it was not and the appeal is dismissed," she added.
Begum, whose family is of Bangladeshi origin, was 15 years old when she left her east London home for Syria with two school friends in 2015.
While there, she married an IS fighter and had three children, none of whom survived.
Begum took her case against the revocation of her citizenship to the appeal court in October last year.
Her legal team argued that the government had failed to consider its legal duties to Begum as a potential victim of trafficking.
But the court ruled on Friday that the risk to national security took precedence over whether she had been a potential victim of trafficking.
In February 2019, Begum said she was left stateless when Britain's interior minister at the time, Sajid Javid, revoked her citizenship on national security grounds after she was found in a Syrian refugee camp.
However, the appeal court said that Begum had not been left stateless as she retained Bangladeshi citizenship through her mother, and that the government did not need to consider whether Bangladeshi authorities would allow her to enter the country.
- Begum to fight decision -
Her lawyers also said the government should have informed her of the decision to revoke her citizenship beforehand.
The appeal court rejected the argument, saying it could allow the "person to make a pre-emptive return to the United Kingdom".
The appeal was against the Special Immigration Appeals Commission's (SIAC) decision in February 2023 to uphold the removal of her citizenship.
Friday's ruling means that Begum cannot return to the UK from her current home, a refugee camp in northern Syria.
After the hearing, her solicitor Daniel Furner vowed that "we are not going to stop fighting until she does get justice and until she is safely back home," suggesting they will make a final appeal to the country's top court.
Begum is one of hundreds of Europeans whose fate has challenged governments following the 2019 collapse of the Islamist extremists' self-styled caliphate.
Begum's lawyer told the SIAC hearing that her client had been "influenced" along with her friends by a "determined and effective" IS group "propaganda machine".
The appeal court accepted that Begum "may well have been influenced and manipulated by others", but added she could "still have made a calculated decision to travel to Syria".
Around 900 people are estimated to have travelled from Britain to Syria and Iraq to join the IS group. Of those, around 150 are believed to have been stripped of their citizenship, according to government figures.