Shamima Begum, who fled to Syria six years ago to join Islamic State, failed to restore her British citizenship after the Supreme Court ruled that she had lost her case.
As a result, she will not be able to return to the UK and fight her case as well as losing her citizenship.
The 21-year-old is still considered a national security threat by MI5 for aligning with a terror group. Lord Pannick QC, who represented Begum, stated that she was unable to put her case together properly in al-Roj camp, where she is being detained, as she is not permitted to use her phone.
Last year, the High Court permitted Begum to return to the UK to fight her case but a Home Office decision appealed against that decision.
A 47-page ruling by the Supreme Court stated that the court of appeal was wrong to make the decision that Begum should be allowed to return to the UK and fight her case.
Concluding this, the Supreme Court added that the court of appeal was wrong to believe that the right to a fair trial prevailed the requirements of national security.