A British-born woman who went to Syria as a schoolgirl to join Islamic State lost her latest appeal against the removal of her UK citizenship, with a judge ruling her possible trafficking was insufficient grounds to reinstate her citizenship.
She was stripped of her British citizenship on national security grounds in 2019, shortly after she was found in a detention camp in Syria.
Her lawyers said they would challenge the ruling.
Begum is currently being held in a detention camp in northeastern Syria.
Begum challenges decision at hearing in London
Announcing the tribunal's decision, Judge Robert Jay said there was a "credible suspicion" that Begum was trafficked to Syria for the purposes of "sexual exploitation" but that the suspicion was insufficient for her appeal to succeed.
Begum's case has been the subject of a heated debate in Britain in recent years, with some saying she forsook her right to citizenship by traveling to join the militants and others arguing she should not be left stateless.
Jay also said British government officials appeared to "see this as a black and white issue," adding in his written ruling that the government's witnesses' evidence to the tribunal "betrayed an all-or-nothing approach."
He said the tribunal was concerned by the security services' "apparent downplaying of the significance of radicalization and grooming."
"History, and sadly the present, is replete with examples of dictatorships attempting to manipulate their subject populations with propaganda and the like," Jay added. "It is commonplace that they succeed."
Begum left London in 2015 at the age of 15 and traveled with two school friends to Syria, where she married an IS fighter and gave birth to three children, all of whom died as infants.
Now 23, she challenged that decision at a hearing in London in November, when her lawyers argued that Britain’s interior ministry, the Home Office, failed to investigate whether she was a "child victim of trafficking".
Her lawyers also argued that then-Home Secretary Sajid Javid had "pre-determined" that Begum's British citizenship should be revoked before he received any evidence from officials.
But lawyers representing the Home Office said Begum's case was about national security rather than trafficking, arguing that Begum had aligned with IS and stayed in Syria for years.