LONDON (AP) — A British woman whose U.K. citizenship was revoked after she traveled to Syria as a teenager to join the Islamic State group has lost an appeal in her fight to have her citizenship restored.

Shamima Begum, now 23, was 15 when she and two other girls from London joined the extremist group in February 2015. Authorities withdrew her British citizenship on national security grounds soon after she surfaced in a Syrian refugee camp in 2019.

The Special Immigration Appeals Commission, a tribunal which hears challenges to decisions to remove someone’s British citizenship on national security grounds, ruled there was a “credible suspicion” that Begum was trafficked to Syria for “sexual exploitation.” It said there also were “arguable breaches of duty” by state bodies in allowing her to travel to the country.

But Judge Robert Jay said that evidence was “insufficient” for Begum to win the argument that the deprivation of her British citizenship failed to respect her human rights. Given that she remains in Syria, UK authorities are not compelled to facilitate her return, the judge said.

“Reasonable people will differ as to the threat she posed in February 2019 to the national security of the United Kingdom, and as to how that threat should be balanced against all countervailing considerations,” Jay said in delivering the decision of the tribunal. “However, under our constitutional settlement, these sensitive issues are for the secretary of state to evaluate and not for the commission.”

Arguing the ruling gave far too much power to the Britain’s home secretary, Begum’s lawyers promised an appeal. Daniel Furner, part of Begum’s legal team, said the case was “nowhere near over.”

“What else this judgment calls out for though is some courage and some leadership from the Home Secretary to look at this case afresh in light of the clear and compelling factual findings this court has made,´´ Furner said. “We are going to challenge this decision.”

Begum had challenged the action of Sajid Javid, the U.K.’s home secretary at the time, arguing that it left her stateless and that she should have been treated as a child trafficking victim, not a security risk.

The British government claimed she could seek a Bangladeshi passport based on family ties. But Begum’s family argued that she was from the U.K. and never held a Bangladeshi passport.

Javid expressed satisfaction with the decision.

“This is a complex case, but home secretaries should have the power to prevent anyone entering our country who is assessed to pose a threat to it,” he said.

The immigration tribunal held a hearing in November on Begum’s appeal. The case threw into sharp relief the larger question of how Western societies deal with people who joined IS but want to go back to their home countries. Thousands remain in camps in northeast Syria.

Begum fled east London with two friends to marry IS fighters in Syria at a time when the group’s online recruitment program lured many impressionable young people to its self-proclaimed caliphate.

Begum married a Dutch man fighting for IS and had three children, who all died.

But her apparent lack of remorse in interviews soon after she surfaced in the refugee camp triggered criticism in Britain. Her tone has changed since then as she reflected on her actions and fought to return home.

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