Begum is now effectively stateless and will likely stay in a detention camp in Syria for the foreseeable future.

The Court of Appeal ruled on Friday that Shamima Begum was lawfully deprived of her British citizenship.

The court said it could be argued that the decision to strip the 24-year-old of her citizenship may be “harsh” but it could also be argued that Begum is “the author of her own misfortune”.

“But it is not for this court to agree, or disagree with either point of view,” the ruling said.

“Our only task is to assess if the deprivation decision was unlawful. We have concluded it was not, and the appeal is dismissed.”

Reporting from outside the court in London, Al Jazeera’s Harry Fawcett said this is not necessarily the end of the road for Begum’s case.

“Her lawyers have a week now to consider this judgement. The chief justice said, if necessary, they can take more time to come back to the court,” he said, adding that lawyers can now take the case to the country’s highest court, the Supreme Court.

Begum, born and raised in east London, left her home in Bethnal Green to travel to Syria and join the group.

She was accompanied by two other schoolgirls, Kadiza Sultana and Amira Abase, with Sultana believed killed in an explosion and the fate of Abase remaining unknown.

Begum’s lawyers had argued that she was trafficked to Syria and the fact that she was a minor when it happened must be considered, but were rejected by government lawyers who argued she did it with full knowledge.

“On both the legislation relating to the European Convention on Human Rights and British common law the judges here determined that it was some four years after [she went to Syria] that the declaration on citizenship took place” and that the home secretary had the right to strip her of citizenship, Al Jazeera’s Fawcett reported.

Her British citizenship was revoked on national security grounds in 2019 after she was found in a Syrian refugee camp. She was pregnant at the time, and the baby, along with her two other children, have died.

She had admitted that she joined the organisation knowing it was proscribed as a “terror” group, and has said she was “ashamed” and regretted joining the group.

Begum, who lived under ISIL rule for more than three years and was married to a Dutch member of the group, has since appealed the decision and says she wants to come back to Britain.

She was born in the UK to parents of Bangladeshi origin but does not have Bangladeshi citizenship.

She could have applied for Bangladeshi citizenship until she was 21, but did not, and the South Asian country has said there is “no question” of her obtaining citizenship now.

The UK Home Office stripped her of citizenship when she was 19 years old, meaning she still had time to file for Bangladeshi citizenship, something that appeared to strengthen the legal basis for revoking her citizenship.

Begum now lives in the al-Roj detention camp in northeastern Syria, where she is likely to stay for the foreseeable future since she is effectively stateless.